Glossary

Deviation from a specific standard within a fixed period of time. The greatest possible accuracy is immensely important in order that the most diverse processes can run synchronously, such as networks, data backup, air traffic, etc. Watches with automatic winding have an accuracy of +/- 30 seconds per day. Chronometers with an appropriate test certificate may only have an error margin of -4/+6 seconds per day.

Acrylic glass is also known as Plexiglas. The latter was registered as a trade mark by its inventor Otto Röhm in 1933 and was common as watch-glass material in the fifties and sixties.

Precise adjustment of a watch or clock.

A top-quality oyster pearl cultured in Japanese waters by Kokichi Mikimoto from 1905 onwards. Now it is cultured mainly in Japan and China. Colours range from white and cream to pink, yellow to green hues.

Watch with striking mechanism (French: réveil) that can be set to any time and is used in pocket watches and also wristwatches.

Actually a variety of chrysoberyl. It bears its name in honour of the Russian Tsar Alexander II. (1818-1881). What makes Alexandrite special is its distinctive colour changing ability. Depending on the type of light it is viewed in, it appears green in daylight but red in candle light. Russian Alexandrites are considered the highest quality. With a Mohs hardness of 8.5, the chrysoberyl is the fourth-hardest mineral after diamond (10), moissanite (9.5) and corundum (9).

Alligator leather is used for high-quality men’s and ladies’ watches. Alligators are not deemed to be true crocodiles. Since the Washington Convention (CITES Convention on International Trade in Endangered Species) in the 1970s, alligator stocks in the USA and China are increasing again. The leather for the production of watch straps comes from alligator farms which are run according to the strictest CITES provisions. Such watch straps have an appropriate CITES certificate.

An alloy is the fusion of two or more metals. In the case of gold, the colour can be changed (e.g. rose gold) or the durability increased.

Fossilised hardened resin, predominantly from the Baltic Sea area. Clear or opaque in mainly honey-yellow shades.

Gemstone, part of the quartz family. Mohs hardness 7. Amethysts in a transparent pure, medium to dark violet are among the qualities sought. In Europe, there are well-known sites in Idar-Oberstein and Maissau in Lower Austria.

Time display usually with minute and seconds hands rotating from the centre of a round or rectangular dial.

Description of a watch which has a time display indicated by only one hand (hour) or three hands (hour, minute, second).

The anchor is a complex part of the mechanical clock which, as part of the anchor escapement, establishes the connection between escape wheel and balance wheel. Due to engagement of the entry or exit pallet in the escape wheel, it ensures the evenly synchronised running of the movement. It is therefore one of the most stressed parts of the mechanical movement.

Classic chain form with oval links made from round wire. It is modelled on ship anchor chains.

Escapement by means of an anchor fitted with pallets which increases the accuracy of portable timepieces. The principle was invented by the Englishman George Graham in 1715. In 1765, Thomas Mudge developed it into the free anchor escapement, also called the Swiss anchor escapement. Since then the escapement has been continually improved and is therefore an important component in almost all mechanical wristwatches.

A power reserve of one year is achieved thanks to a larger gear train, especially slow release of the mainspring and an energy-saving escapement. So the anniversary clock only has to be wound once a year and is usually fitted with an energy-saving, horizontal rotating pendulum.

Watches with annual calendars only have to be corrected manually once a year at the end of February. Watches with full calendars have to be corrected every month and watches with perpetual calendars only at very long intervals.

Electrolytic process used to produce oxide layers on metal surfaces. A bonded oxide finish is formed during the anodisation process. Anodising is used to protect metal surfaces from corrosion.

An applied ornament or a fitting is referred to as an appliqué.

Blue variety of beryl. Highly valued as a gemstone due to its high Mohs hardness of 7.5 to 8. The most important sites are in Brazil, Nigeria, Kenya, Mozambique, Madagascar and Pakistan.

The Asscher cut is a diamond cut shape and due to its shape and brilliance is on a par with the brilliant cut. It is also referred to as the square emerald cut.

The division of a day into 24 hours is known as astronomical hours. This division into hours is used, for example, in watches for military use (military time: USA and Canada).

This is a mechanical movement which, unlike manually wound movements, is not wound manually but rather automatically by the wrist movement of the watch wearer. A rotor (rotating weight) moving in both directions winds the mainspring inside the barrel.

This type of mechanical watch obtains its energy due to the natural arm movements of the watch wearer. In this case, the mainspring is wound up by a small weight rotating in both directions.

The autoquartz drive was developed by the major Japanese manufacturer Seiko and combines an automatic movement with quartz control of the escapement. The watch therefore runs without a battery and with quartz precision.

This is a variation on the military observer watch. They have large luminous digits and hands as well as black dials which ensure optimum readability. They are usually fitted with a soft iron inner case as protection against magnetism. In addition to accuracy and the functions important for pilots, such as a tachymeter scale on the bezel or as an inner ring surrounding the dial, particular attention was paid to a robust design and easy operation, for example using fluted bezels and winding buttons.

a.m. is the abbreviation for the Latin term “ante meridiem” (English: before noon). In English-speaking countries, it describes the time from midnight to noon and is particularly important in the case of digital clocks and watches.

Rectangular stone cut shape with step-like facets.

This is a rectangular movement, used mainly in ladies’ watches. The gear train is arranged on two different levels for reasons of space.

Timing regulator (time divider) of pocket watches and wristwatches. The balance wheel with the concentrically oscillating balance spring ensures the desired number of oscillations. The watch is regulated by changing the effective spring length.

The name used for the balance in English and French.

Balance spring made of a temperature-resistant nickel-iron alloy. Part of the balance, its outer end is attached to the balance cock, its inner end to the balance staff. Abraham-Louis Breguet improved the isochronism by inventing the flat balance spring. The latest developments in this field are balance springs made of silicon.

Spherical clasp of a necklace or collier.

A variation of the channel setting. Each gemstone is set between two bars of precious metal.

Cylinder-shaped box used to protect the mainspring, one end of this spring being attached to its wall. The other end is connected in the barrel arbor.

Double barrel in which two barrels are linked in series to achieve the longest power reserve possible.

Plain bearing made of synthetic rubies, which is recessed in the bottom plate or bridge, in which the pivot of the gear shaft rotates with only minor wear. Ball bearings for automatic oscillating weights are also among the bearings and count as the second type of bearing in the movement.

Rim fixed to the upper side of the watch case. As a design element of the watch, the bezel is either fixed or, because of the additional functions linked to it, can only rotate in one direction to prevent reading errors. A bezel may be provided with a tachymeter scale, for example, or in a diving watch with a scale for the dive time.

Also referred to as flush setting. A strip-shaped ring of the jewellery material is driven over the girdle by machine or by hand using a hammer.

Usually used in chronographs up to the 1960s for making short time measurements. Most watches are now fitted with uni-directional rotating bezels to prevent reading errors.

Up to the invention of the auto-compensating balance spring, the bimetallic compensation balance was used in high-quality mechanical watches (bimetallic rim, outside brass, inside steel).

Topaz is one of the precious gemstones. It has a Mohs hardness of 8 and due to its relative abundance is also used for large, high-quality pieces. In contrast, the blue topaz is rare and is also referred to as “precious topaz”.

Bottom plate of the movement in large and small watches with drilled holes for supporting all the shafts of the gear train. The bottom plate may be round, square or oval. The top plate is usually partially cut out to create space for the balance and escapement. Sometimes up to three bridges also take over the function of the top plate. Glashütte watches often identified by an additional decorated three-quarter plate.

Movable ring on the pendant, the tubular part attached to the case centre section of a pocket watch, to which the watch chain is attached. The bow also acts a protection for the crown.

Jewellery bracelet, in various precious metal designs, plain, with coloured gemstones or set with diamonds, often part of a collection or set of jewellery.

Copper-zinc alloy which has been used in watches since the middle of the 16th century for the production of bottom plates, bridges and the gear train.

The Breguet balance spring was developed by Abraham-Louis Breguet in 1788. The raised outer end curve of the balance spring extends in a precisely calculated curve above this spring and is known as the Breguet overcoil. As a result, the balance spring can expand equally in all directions.

Bearing mount which carries the upper bearing of the train and the anchor. Always screwed to the bottom plate on both sides, it spans the main plate like a bridge.

Fire or brilliance of a cut diamond. This depends on the type of cut and the execution of the cut with the proportions also playing an important role. Inclusions, depending on their size, can considerably reduce the brilliance.

The brilliant cut diamond is a cut diamond with 57 or 58 facets. The cut was developed around 1910, is characterised by a high level of brilliance and is one of the most popular diamond cut shapes.

Piece of jewellery which is pinned to clothing by means of a pin attached to the setting. In ancient times and in the Middle Ages it was also used as a cloak clasp.

The strap, which is attached to the watch case, is closed with a buckle. Holes are punched through the longer part of the strap. The pin with associated U-shaped metal clip, which prevents the pin from slipping out of the hole, is located on the shorter part of the strap.

Central European Time, time zone for Central Europe.

Abbreviation for Contrôle Officiel Suisse des Chronomètres [Swiss chronometer test centre], an independent organ which is officially authorised in Switzerland to award the title of “chronometer”; to successfully tested movements.

This is a gemstone cut shape with a flat underside and a rounded, domed upper surface.

Astronomy-derived division of a year into days, weeks, months which goes beyond the normal display of seconds, minutes and hours.

The calibre indicates the shape and size of a movement. The calibre number denotes the type of movement of a watch. If necessary, this number can be used to find appropriate spare parts.

In watchmaking, calibre (also called caliber) is the term for a specific movement.

Refers to the relief-like carving of a motif out of a gemstone.

Clasp of a bracelet or chain, held by a spring mechanism, which prevents accidental opening.

Carat (ct) is the unit of measurement for the purity of gold. The gold content of an alloy in carats corresponds to the proportion by weight in 1/24 parts. Carat is also the unit of weight for coloured gemstones and diamonds. 1 carat weighs 0.2 grams.

Legal unit of measurement for diamonds and gemstones, specified in Germany with “Kt” and in Austria and Switzerland with “ct”. The metric carat was specified in 1875 and equate to 0.2 grams.

Unit of measurement for the purity of gold. 14 ct indicates a 58.5 percent proportion of pure gold (585/1000), in 18 ct the proportion of pure gold is 75 percent (750/1000). Added to this may be silver and copper as pure gold is too soft for jewellery making or watch cases. The colour of gold depends on the type and proportion of these alloys. The appropriate precious metal hallmark is mandatory and guarantees the purity.

Belongs to the mineral group of quartz. The predominant colours are blood-red or brown-red, mostly stained.

A receptacle designed for jewellery or watches which is used for protection and storage.

The case is used to protect the movement of the dial and the hands against dirt and moisture. It is manufactured in different designs and materials. Water-resistant or watertight cases which have special gaskets are often preferred for wristwatches.

This specifies the size of a watch and is not the same as the movement inside which may be smaller and is then fixed in the case with a movement retaining ring. For along time the size of men’s watches was 38 mm diameter but sizes of more than 40 mm are currently common.

Pressed or screwed. A screwed caseback can be sealed better and protects the movement against dust and moisture. In addition to the serial number, the caseback usually specifies the model type, water- and shock-resistance and limited edition number. The sapphire crystal back common to many watch brands allows viewing of the watch’s inner workings.

Bezel insert or monobloc bezel developed and patented by Rolex in 2005, made of extremely hard, corrosion-resistant, virtually scratchproof ceramic whose colour is unaffected by the sun’s ultraviolet rays. The moulded graduations and numerals are coated with either a thin layer of gold or platinum via Physical Vapour Deposition.

Braided cord of high-quality textile material (e.g. silk) which is usually worn with a pendant.

Very popular gemstone from the mineral group of quartz, Mohs hardness 7. Colour loss may occur with excessive exposure to black light (UV light), direct excessive sunlight or spotlight irradiation. A distinction should be made between natural and dyed chalcedonies. One variety of these is chrysoprase in apple or emerald green which is also imitated by green-dyed agate. However, according to CIBJO regulations (The World Jewellery Confederation), this must be disclosed.

Chamfering is part of the finishing of an ébauche movement (or raw movement). This means that the sharp edges of a bottom plate or bridge are chamfered to 45 degrees and then polished.

Arrangement of coloured gemstones or diamonds, resting side by side in a double-walled setting.

Metal ring, usually gold, for holding the bearing jewel of the shaft journal. A distinction is made between screwed and pressed chatons.

A claw setting developed from the bezel setting with four, six or eight claws. Traditional type of setting for solitaire rings.

A type of necklace fitting tightly around the neck.

Luminescent display for hands, hour markers, and the bezel zero marker on divers´ watches using a special material emitting a long-lasting blue glow, and offering almost double the luminosity duration of standard phosphorescent coatings.

New escapement developed and patented by Rolex offering a 15% improvement in energy efficiency for this key component of the movement, resulting in over 10 hours of additional power reserve. Made of nickel-phosphorus, it is also insensitive to magnetic interference.

The name is derived from the Greek terms chrónos for “time” and gráphein for “writing”. This describes a watch that permits short time measurements by means of a pushbutton. Nicolas Mathieu Rieussec invented the first chronograph in 1821. A chronograph has hours, minutes and seconds hands. Chronographs are usually equipped with two pushbuttons but there are also models with only one pushbutton which can be pressed to activate the start/stop and reset function of the seconds hand. By pressing the button, a chronograph’s hands can be activated, deactivated or returned to the zero position. Different time periods can be measured depending on the watch version.

The doctrine of time, made up of the Greek terms chrónos for “time” and lógos for “teaching”. Sequence of a series of events in a specific relationship.

Protected term which may only be used after an official testing procedure (e.g. Swiss COSC). The watch is tested under a wide range of conditions. An official certificate confirming that the tolerance limits have not been exceeded is then issued. In some test procedures, the uncased movement must pass these tests, in others the cased movement is subjected to the series of tests.

This certificate is only issued if a watch has successfully passed the timing accuracy test criteria (e.g. COSC).

Belongs to the mineral group of quartz and has a Mohs hardness of 7. As a gemstone, the true citrine is rare. The name is derived from its predominantly lemon yellow colour. Colour: light yellow to golden brown.

Clarity is one of the four main determining criteria (4Cs: cut, clarity, carat, colour) for the quality of diamonds and coloured gemstones.

Clarity is also one of the four main determining criteria (4Cs: cut, clarity, carat, colour) for the quality of diamonds.

At least four metal claws or prongs, worked out of the gallery of the ring, hold the stone securely in a claw or prong setting.

Setting in which a diamond or coloured gemstone is held securely by claws or prongs and is thus shown to its best advantage.

Recommended at 3 to 5 year intervals as a service to preserve the value of high-quality mechanical watches. The parts of the movement intended for this are cleaned and re-oiled, wear parts such as gaskets in the case are replaced and signs of wear and tear on the case are largely removed.

Not all coloured gemstones are cleavable, their cleavability depends on the internal crystalline structure. The stones belonging to the quartz group are not cleavable at all.

Description of a usually close-fitting necklace with a length of approximately 40-42 cm. Colliers in gold or platinum are often set with diamonds, rubies, sapphires or emeralds.

Colour is one of the four main determining criteria (4Cs: cut, clarity, carat, colour) for the quality of diamonds.

Colour is one of the four main determining criteria (4Cs: cut, clarity, carat, colour) for determining the quality of diamonds. The colour tables of the CIBJO [Confédération Internationale de la Bijouterie, Joaillerie, Orfèvrerie, Perles et Pierres or World Jewellery Confederation] as well as of the GIA [Gemological Institute of America] are binding. Diamonds with clearly visible, natural intrinsic colouration (fancy coloured) form a special category.

Colour plays a huge role in natural, untreated coloured or precious gemstones since this is a feature that significantly increases the price per carat.

Part of the column wheel chronograph where the start, stop and zero/reset positions of the hands are controlled via a column wheel, also known as the ratchet wheel. Expensive and challenging technical design which was widespread in the 1930s and 1940s and is currently being used more often.

One or more additional mechanisms of movement, such as a striking mechanism, alarm, calendar or chronograph.

Central control of the hour and minute hand from the centre.

Heavily branched coral colonies from coral reefs in red, pink, white, but also black and blue are used for high-quality pieces of jewellery. Mohs hardness: 3-4. Red noble coral is particularly sought-after.

Cord created from spirally twisted and interwoven gold wire which is worn as a necklace.

The crown or winding button sits on the upper end of the winding stem which creates the connection to the movement. It can easily be pulled out to set the watch, two other positions are used to set the date or weekday. In the case of diving watches, the crowns are usually screwed down to protect the watch against the ingress of water and moisture.

Concealed folding clasp designed and patented by Rolex, opened via an articulated Rolex crown.

Items of jewellery for men, mainly made of gold, used instead of conventional cufflinks to underline a businesslike elegant appearance.

Cushion cut named for its shape. Squarish shape with rounded corners, similar to those of a cushion.

Cut is one of the four main criteria (4Cs: cut, clarity, carat, colour) for determining the quality of diamonds.

Cut is one of the four main criteria (4Cs: cut, clarity, carat, colour) for determining the quality of diamonds.

The date display on watches shows the day, week, month or year. The display may be carried out by a so-called hands date (month) from the centre or may be digital by means of a number disc in the date window (day/month). The perpetual calendar which takes into account the changing length of February and leap years is a special function.

The watch glass has an integrated magnifying glass for better readability of the weekday and month display.

Due to constant wear, leather watch straps are exposed to external influences such as moisture, abrasion or perspiration. The result is detanning which may cause the watch strap to harden and break.

The dial is divided into equal sections to indicate the time of day. The dial is usually divided twelve times by means of indices (e.g. digits or dashes) to indicate the hours, and 60 times with dashes to indicate the minutes and seconds. 

Probably the most popular gemstone is the hardest naturally occurring mineral with a Mohs hardness of 10. The weight is measured in carats with one carat equal to 0.2 grams. The type and quality of the cut ignites the fire of the diamond which has a very high refractive index. Because of its brilliance, the brilliant-cut diamond is one of the most common and most popular cuts. Diamonds are rated internationally by the 4 Cs: Cut, Clarity, Carat, Colour.

Indices which indicate the hours by means of diamonds set on the dial of a watch – usually brilliant-cut.

Physical methods can be used in such a laboratory to precisely analyse the quality of a coloured gemstone or diamond. These methods are used to determine whether a coloured gemstone or diamond has been subjected to physical, thermal or chemical treatment and whether it might even be synthetic, i.e. a fake stone.

As early as the 19th century, clocks were produced which used small falling number plates instead of traditional hands to display the time. Nowadays, the time on digital clocks is displayed by means of light-emitting diodes or liquid crystal.

Display using digits on rotating discs in a specially provided window. In contrast to an analogue display using hands.

Form of the electronic, mainly digital time display.

Specially equipped wristwatch with uni-directional rotating bezel for setting the dive time and a dial which is easy to read under water. Special gaskets on the caseback and crown and – if present, the pusher guarantees absolute water resistance of the case.

Also known as a split-second chronograph. It has two second hands, one of which is superimposed over the other. While one hand moves continuously, the other one can be either stopped, started or reset to zero independently in order to measure a split time.

Description of a watch whose functions, such as a second time zone or special complications, are displayed on the front and back.

The end-of-life indicator is a display function of battery-operated watch which alerts the wearer 4-7 days in advance, by the second hand jumping noticeably in 4-second intervals, that the battery is exhausted and battery replacement is necessary.

Stud earrings or earrings with diamonds or coloured gemstones.

Creoles, mostly hollow with different types of closures.

Rapid extension link system developed and patented by Rolex that allow the wearer to easily extend the watch bracelet by 5 mm for greater comfort.

Eight-day clocks have a bigger barrel and an additional gear wheel (week wheel) in the movement between the minute and third wheel. For this reason they only need to be wound every eight days.

In electroplating, a metal coating is applied to an item of jewellery, for example, using electrolysis. Electroplating can be used to either result in a change in colour or also to create a harder surface finish. Rhodium-plating gives white gold a uniformly fine surface finish and hence improved brilliance. Rhodium-plating of silver prevents it from becoming tarnished (oxidisation of the surface). This technique can also be used for silver or gold-plating objects.

Part of the beryl group like aquamarine and beryl. Mohs hardness 7.5 – 8. Colour: Green in all its different variations, emerald green, light green, yellow-green or dark green. Insignificant natural inclusions are not regarded here as flaws but rather as signs of a natural and therefore genuine emerald. These inclusions are also referred to as “jardins” (French: garden).

Octagonal step cut, the classic cut specially used for emeralds.

A gemstone (diamond in high-quality watches) is often used as the endstone. It lies with its flat side above the pivot jewel on the bearing of a shaft journal or balance staff. This is to minimise the journal friction.

Usually a solitaire ring worn on the ring finger of the left hand. Symbol of the mutually given promise to enter a marriage.

The cutting of monograms or ornamentation into metallic or non-metallic (e.g. mother-of-pearl) surfaces using an engraving stylus.

Guilloche machine for decorating watch cases or dials with high-precision regular patterns.

Traditional decoration technique on the case of a watch or on the bottom plate and bridge using an engraving stylus to apply ornamentation or a name engraving. Complicated patterns on a dial or cases are applied using a guilloche machine.

A watch with equation or equation of time displays the deviation of mean solar time, according to which a day is divided equally into 24 hours, from true solar time as is displayed by a sundial.

The temperature or position of the movement can affect the accuracy of a clock. The error margin is the difference between two different gears.

The escapement is located between the train and the regulating organ and suppresses or meters the oscillations of the movement. Depending on the movement of the escapement wheel, a distinction is made between verge escapement and deadbeat escapement. In the detached (detent) escapement, the balance wheel swings after every pulse without being connected to the escapement.

As the last wheel in the gear train, the escape wheel together with the anchor forms the escapement. It transfers the force to the anchor due to its special shape. It moves at a higher speed than all the other wheels of the movement.

Exclusive 18 ct pink gold developed, patented and produced by Rolex in its own foundry. The alloy owes its unique colour to its special composition that helps preserve the alloy`s pink colour over time.

Flat cut surface on a diamond or coloured gemstone.

Term used for diamonds with clearly visible, natural intrinsic colouration (e.g. blue Wittelsbach/Wittelsbach-Graff diamond) in shades such as blue, yellow, orange or brown which are not frequently found. Black diamonds are also included.

Special type of cut, not round as in brilliant cut. It is used if the shape of a diamond does not permit any other shape of cut.

Filing is one of the fundamental techniques that a gold or silversmith must learn to master expertly. Only by perfecting the art of filing is it possible to execute each stroke of the file flawlessly. Apart from flat files, round files, triangular files, half-round files or square files in four sizes and teeth designs (linear grooves on the file blade) are used in filing. Diamond files, which are set with diamonds in an electroplating process, are particularly suitable for working with hardened steels.

In clocks with mechanical oscillation systems, fine adjustments are made to establish good timing or to eliminate irregularities of isochronism.

Fine regulation (also fine adjustment) is a work process used in precision timepieces on escapement and gear regulator with the aim of regulating the watch as accurately as possible. It can also refer to the shape of the regulator which is adjustable in small steps in chronometers.

Finishing work on a clock during which the train and barrel are installed between bottom plate and bridges or finish-machining of the gear train.

Colour play specifically in diamonds due to refraction of the light and divergence into spectral colours (dispersion).

A fold-out extension system fitted on the Oyster bracelet of the Rolex Deepsea and Sea-Dweller 4000 divers’ watches. It allows the Oyster bracelet to be lengthened by 26 mm for wear over a diving suit.

Makes adjusting the bezel easier in the case of a uni-directional rotating bezel, the knurled bezel is another version. Smooth bezels are not usually rotatable.

In a split-seconds chronograph, this function in the movement allows the stop hand to be reset immediately to zero by pressing the button during a time measurement.

The four main criteria (cut, clarity, carat, colour) for determining the quality of diamonds.

Balance spring or hairspring without regulator for altering the effective spring length.

Number of full oscillations of the balance wheel per second. The oscillation period is shown in Hertz (1 Hz = 1 full oscillation per second).

Cultured pearl either with nucleus, but mostly without nucleus, from bodies of freshwater in Japan (Lake Biwa) and China. The production of Biwa pearls, however, ceased in the mid 1970s. Freshwater cultured pearls now come mainly from China. The predominant natural colours are white rose, orange, golden yellow, brown and blue. These pearl colours are also frequently bleached.

Watches with date, weekday and month display. In contrast to the perpetual calendar, the different monthly lengths have to be corrected manually by means of a quick correction. A full calendar is usually also combined with a moon phase display.

The GIA (Gemological Institute of America) was founded in 1931 and is today the best-known and most highly respected authority in the world that, as a non-profit organisation, carries out meticulous appraisals specifically for diamonds. Its assessment criteria are considered as the most stringent. Diamonds with a GIA certificate therefore have the most lasting value. A certificate of this kind is extremely useful when selling diamonds or for an insurance claim. The GIA certificate (GIA Diamond Grading Report, GIA Diamond Dossier) includes the following points: shape and cutting style, quality of cut, polish, dimensions of the stone, weight, colour, clarity, symmetry and fluorescence. The proportions, the criteria for clarity and the GIA grading scale are specified precisely with illustrations.

GMT is the abbreviation for Greenwich Mean Time as the zero meridian of world time runs through the town of Greenwich in southern England. The international time display of the 24 different time zones is always based on GMT.

To prevent the ingress of moisture into the interior of a watch and thus to prevent damage to the movement or dial, watches are usually provided with gaskets in the rebate of the case cover. In some cases, the winding button may also be fitted with a similar gasket.

Includes all gear wheels (spring wheel, minute wheel, third wheel, second wheel) and drives of a movement which transmit the energy of the wound mainspring to the escape wheel.

A gemstone (e.g. chalcedony) decorated with a recessed image.

Branch of mineralogy dealing with the teaching of coloured gemstones and precious stones.

GIA, founded in 1931. An independent non-profit organisation that provides information and protection to retailers as well as end users through research, knowledge transfer and laboratory testing of coloured gemstones, diamonds and pearls.

Mostly opaque, that is non-transparent, unlike coloured gemstones. Found comparatively frequently.

The more accurate term for this is coloured gemstone. Occurs less often compared to precious stone.

Decoration of undulating lines, like waves, on the bottom plate of a movement for embellishment, with no practical function.

Synonym: quartz, more accurately: fine-grained, grey jasper dyed with Berlin blue. Hardness according to Mohs: 7. Colour: blue, in a variety of shades. W: In the case of repairs with heat-treatment and activities using caustic solutions, salts and galvanic baths, the stone should be removed from the setting or should be protected with protective covers. Alum liquor can also alter its surface. The same applies to Neacid liquor. Avoid silver cleaning baths when processing stones in silver jewellery. Also avoid ultrasonic cleaning with a high-intensity caustic solution. H: Popular gemstone used as a cheap substitute for lapis lazuli. Do not clean in ultrasonic unit as the surface of the stone can become spotted. Spotlight illumination and sunlight bleach the stone’s surface. Not always available as calibrated cut.

Narrow horizontal line separating the crown (top) of a diamond from the pavilion (bottom). The cut of the girdle must be very precise.

Usually made of tempered sapphire crystal. Allows the wearer to view the movement.

Rare valuable precious metal and therefore desirable in alloyed form as a high-quality jewellery material. No oxidation, chemically resistant, easy to machine and polish. Based on the legally required hallmark, the purity of gold can be seen on jewellery or watches.

Exclusive dials obtained by a process of gold crystallization developed by Rolex in its own foundry. Via electrodeposition or PVD, the dials can be coated either with yellow gold, rhodium or pink gold, or decorated with motifs.

Pocket watch or wristwatch which, in addition to the normal function, must have at least a chronograph function, a minute repeater and a perpetual calendar.

Aventurine or aventurine quartz. Mohs hardness 7. Used mainly as a cabochon in jewellery.

To obtain a surface finish of consummate quality for jewellery and watches, stainless steel, platinum, gold or high-tech ceramics are worked using the relevant processes or mechanical methods (grinding with polishing granulate). Grinding is carried out before subsequent polishing.

Term used for the grinding and polishing of larger movement components such as bottom plates and bridges.

Elaborate decoration of watch cases or dials with high-precision, regular patterns using a guilloche machine.

Hoge Raad voor Diamant Antwerpen. One of the most renowned gemmological laboratories worldwide, known for its highly reliable analyses, the grading and certification of diamonds.

HRD (Hoge Raad voor Diamant) is considered to be one of the most acclaimed gemology laboratories in the world on account of its very reliable analyses. The HRD Diamond Certificate and the HRD Diamond Identification Report cover all important characteristics of each diamond that has been analysed (cf. criteria for GIA Certificate).

Legal marking of the precious metal content of a piece of jewellery (14 ct or 18 ct, and above 800 for silver or 950 for platinum). Up to 2002, pieces of jewellery in Austria had to be marked with three hallmarks: the official hallmark, the purity number and the name mark. Now the purity number and name mark are sufficient. Pieces of jewellery which are too small to be punched are exempted from hallmarking.

Instrument for the analogue time display of hours, minutes and seconds (three-hand watches, also sometimes the date (date hand). Baton hands on sports watches are often coated with luminescent material.

In a hand-wound watch, the mainspring must be tightened daily by winding the crown.

Scratch hardness in the case of coloured gemstones but also grinding hardness. Testing of the scratch hardness is attributed to the mineralogist Carl Friedrich Christian Mohs.

Mohs hardness scale (grade 1 – 10), named after Carl Friedrich Christian Mohs, a mineralogist in the early 19th century. From 1812 onwards Mohs, as a professor of mineralogy at the Joanneum in Graz, developed the classification of minerals which is named after him, which mainly referred to the physical properties (shape, hardness, brittleness, specific gravity) and is still applicable to this day.

Quartz variety, also known as tiger’s eye/cat’s eye/bull’s or ox eye depending on colour, popular gemstone with bands of parallel layers in dark blue, blue-grey or blue-green, mostly polished and set as a cabochon. Found in South Africa and western Australia.

Heart-shaped cut for a coloured gemstone or diamond.

Valve for diving watches to regulate pressure during the diving phases.

A security valve patented by Rolex in 1967 for deep-sea diving. During the decompression phases that professional divers undergo in hyperbaric chambers, the helium valve automatically regulates the excess pressure trapped inside the watch case, without affecting the waterproofness of the watch. It features on the Sea-Dweller 4000 and the Rolex Deepsea Professional divers’ watches.

Just like normal Smartwatches, hybrid Smartwatches have functions such as activity tracking, e-mail and text message functions, etc. but their design is analogue. They combine innovative digital technology with classic watch design.

Shock protection of the balance staff developed in 1933.

Natural gemstones may have inclusions of liquids or other minerals which were embedded in the course of the creation. Inclusions, while guaranteeing the authenticity of a stone, also reduce its quality.

Another term for display: in addition to displaying the time of a watch, it includes the indication of complications such as calendar, moon phase or second time zone.

IGI, gemmological institute established in Antwerp in 1975. Grading and certification of coloured gemstones and diamonds.

Colour play on the surface of precious stones.

Pendulum law discovered by Christiaan Huygnes in 1656 which states that a pendulum or a balance maintains a constant frequency or oscillation period at different amplitudes.

Jadeite, nephrite. Mohs hardness: 6 to 7. Green in more or less strong shades but also yellow, grey, bluish, reddish, brown and ivory white. Jadeite in emerald green (Imperial jade) is extremely precious and therefore very sought-after. Do not clean in ultrasound equipment or silver immersion baths. Silver cleaning cloths are advisable for jadeite in silver mountings.

Invented in 1883 by Austrian engineer Josef Pallweber, and since then further improved digital mechanism for displaying the hour with the utmost precision. When changing to the next hour, the display jumps over, which requires a significant yet extremely precisely metered input of energy. The process is also known as “springende Stunde” (German) or “heure sautante” (French).

A special seconds display (French: seconde foudroyante), a complication used only rarely in fine watchmaking. The seconds hand rotates with a period of one second, this takes place in four or five jumps and enables the measurement of 1/4, 1/6 or 1/8 of a second.

Shiny metallic flashes of colour, specifically in labradorite.

Irregularity in the atomic structure of the crystal lattice of a coloured gemstone or diamond.

Used in wristwatches for watch straps. Mostly hand sewn and available in various leather effects (e.g. alligator leather).

Made of knotted leather strips, can be worn as a bracelet or necklace with a pendant.

Limited number of a watch model with visible numbering on the side of the case or the caseback (e.g. 88/150) produced for special occasions (e.g. company or model anniversary, especially exclusive design).

Inside of the leather watch strap. The lifespan of the watch strap depends on the quality of the lining.

For a certain location, local time specified depending on the meridian (longitude).

Top quality diamonds or coloured gemstones are described as loupe clean if they are free from internal inclusions at 10x magnification.

Term for the time period during which the moon passes through all the phases. This corresponds to approximately 29.5 days. In mechanical watches, the moon phase display is a popular complication.

Typical pearl lustre, brilliance of the pearl surface.

Important instrument for watchmakers. Also an essential aid for better readability in watches with date (date magnifier/cyclops).

The mainspring consists of a metal spring which is hooked into the barrel arbor and the barrel wall. Its task is to store the energy generated by the tension when winding up the watch.

A wristwatch or pocket watch is wound daily by winding the crown by hand to tension the mainspring in the barrel. This was the most common winding method for watches until the 1930s. The Rolex Oyster Perpetual of 1931 is considered to be the first fully functional automatic wristwatch with self-winding rotor; the principle was patented for the company worldwide in 1932.

Watchmakers who produce both the movement and also the other essential parts of the watch itself are considered to be watch manufacturers.

Many manufacturers use a trade mark as a signature next to their name.

Also referred to as manufacturer-made calibre. A calibre developed and manufactured by a watch manufacturer itself.

(Navette: French for “little boat”) Two tipped cut: oval cut shape with two tips at the opposing ends.

iving a matt finish to individual sections of an item of jewellery or a watch is used as a method of design in order to obtain a striking contrast between brilliant polished surfaces and matt surfaces. Precious metal is given a matt finish by means of pickling, carried out by hand, using emery paper and also pumice stone, or mechanically, using a sandblaster and special granulate.

Watch with wind-up mainspring and a gear train that transmits the force from the spring to the timing regulator.

Mineral glass is used in wristwatches instead of the acrylic glass previously common. Mineral glass is more scratch-resistant but not as durable as sapphire crystal.

Peripheral minute division on the outer edge of the dial, consisting of two delicate lines running in parallel between which the division for the minutes is mounted.

Watches with built-in striking mechanism which repeat the last hour struck on demand are called repeater watches. The minute repeater is a refinement of this: Here the watch can be made to strike the hours, quarter hours and minutes at different pitches by operating a slide which winds up a striking mechanism.

Anchor wheel, anchor and balance are located in a cage mounted on the shaft of the seconds wheel. The cage rotates about its own axis once a minute to compensate for any position errors.

Part of the gear train with minute hand sitting on it. The minute wheel rotates about its own axis once in 60 minutes.

Self-contained component of a watch which is mounted on an ébauche (unfinished movement) (e.g. chronograph module).

This watch function which belongs to the grand complications indicates the constantly changing moon phase. This requires a mechanically complex construction which is linked to the date function. The moon symbol in the dial cut-out shows the waxing and waning moon.

Part of the feldspar group. Mohs hardness: 6 – 6.5. Gleaming colourless to bluish white, pressure-sensitive.

Naturally grown product from the shell of gastropods or molluscs. The layered structure of the shell gives rise to the so-called mother-of-pearl iridescence. Mother-of-pearl has the same properties as natural or cultured pearls and must be handled accordingly. The natural material can be dyed and it can also be engraved or guilloched (engine turned).

In addition to being used in jewellery, mother-of-pearl is also used for the dial of elegant ladies’ watches.

Gears under the dial separate from the movement via which the hands are driven.

Term for the clockwork movement.

The fully functioning assembly of all the main timekeeping organs of a watch. They include the barrel and mainspring, the gear train and the escapement together with the oscillation system.

See balance spring

Virtually anti-magnetic and stainless as well as temperature-neutral alloy which is used for the production of balance springs. The rate of watches fitted with them is very steady.

Clock with only one hand which displays the hours. Original way of displaying the time on church tower clocks and early pocket watches which some clockmakers are also using again now.

Natural onyx is an agate and belongs to the quartz group. Mohs hardness: 7. With alternating white and black layers (layered stone). Apart from being used as a ring stone, onyx is used as the lower layer in expensive opal doublets.

Opal is part of the quartz group, Mohs hardness 5-6. Differentiated into iridescent noble opals, yellow-red fire opals and ordinary opals. Contains a small amount of water, therefore sensitive to pressure and impacts.

The weight attached to the outer edge of the rotor or the entire rotor of an automatic watch which ensures the mainspring is wound via a special gear mechanism.

Facetted oval cut shape for coloured gemstones.

Folding clasp with a cover, patented by Rolex.

Innovative bracelet developed and patented by Rolex. It combines the robustness and reliability of a metal bracelet with the flexibility, comfort and aesthetics of a rubber strap. At its core lies a superelastic metal blade overmoulded with high-performance black elastomer.

Folding clasp with a cover and a safety catch, fitted on the Oyster bracelets and leather straps of a number of Professional models. Patented by Rolex.

Hairspring developed, patented and manufactured by Rolex in an exclusive alloy which has the advantage of being paramagnetic, offering great stability to temperature variations and remaining up to 10 times more accurate in case of shocks than a traditional hairspring. It thereby enhances the movement’s chronometric performance.

Shock absorbers developed and patented by Rolex which increase the shock-resistance of sensitive movement components, notably the balance staff, by up to 50%.

Identically designed pair of rings used by two people joined in love to express this connection visibly.

Pavé (French: paved) refers to a jointless setting where the diamonds are generally set very closely together on a piece of jewellery.

Pear-shaped diamond cut used mainly for pendants or earrings. Also known as drop cut.

Natural (designation: pearl) or cultured (designation: cultured pearl). Basically, a distinction is drawn between saltwater and freshwater pearls of molluscs but also of gastropods. Mohs hardness 3 – 4. Cultured pearls in a wide range of colours and qualities are used for jewellery. Size, shape, colour and lustre are significant for their quality. Baroque pearls is the term given to individual pearls which have a special asymmetrical growth form. Pearls react sensitively to excessive heat, galvanic baths, ultrasound cleaning, silver immersion baths and cosmetics such as hair spray or deodorants.

Winding system for automatic movements, developed by Albert Pellaton, then technical director at IWC Schaffhausen, and patented in 1946.

This is used to accentuate a necklace or collier and may be part of a jewellery set which features the same stylistic motifs on ring and earrings.

Type of mineral: Magnesium silicate. Mohs hardness: 6.5-7. Predominant colours: yellow-green, olive green, brownish. Is often referred to mineralogically as chrysolite or olivine due to its special colour.

Also referred to as cloud cut, decoration applied to bottom plates, bridges or cocks consisting of small, overlapping circles. The word is French and means, literally, “pearling”.

Self-winding mechanism with a free rotor invented by Rolex in 1931 which allows the mainspring of the watch to be wound using the natural movements of the wrist. The Perpetual rotor provides a constant and optimal source of energy for the watch movement as well as increased comfort of the wearer.

Full calendar with day, date, month and moon phase. It automatically takes into account leap years and sometimes indicates them by means of a leap year display. Having set the perpetual calendar once, any readjustment is not usually necessary.

The rarest, purest and most valuable precious metal. Platinum is anti-allergenic and stronger, tougher and heavier than other precious metals which is why is worked with special tools and techniques. Apart from being used for high-quality jewellery, platinum is also used for the production of watch cases. The precious metal content of platinum must be legally identified with a hallmark (Pt950).

Term used for the property of exhibiting different colours and depth of colour when viewed from different directions in coloured gemstones.

Watch in small format which is worn on a watch chain. Pocket watches have been in existence since the end of the 15th century. Hunter models have a push-button sprung cover which when closed protects the watch glass. Until the 1920s, pocket watches were the most popular men’s and women’s watches in the widest variety of designs and qualities. Then they were replaced by wristwatches.

When working metal workpieces during watchmaking or clockmaking, some unevenness, burrs or residue from welding are usually left and these need to be removed. Cases made from high-tech ceramics are also polished during the production process. However polishing can also eliminate scratches from an item of jewellery or the case or band of a watch. Polishing is carried out in several stages. Various abrasives are used for this (including buff wheels, leather and felt buffing wheels, brushes). Especially with watch cases and bracelets made of stainless steel or gold, special care needs to be taken during polishing to ensure that edges are not polished until round. Polishing titanium or platinum is considered to be one of the most challenging tasks in polishing due to the material properties.

Varying regulation behaviour of watches in different positions.

Indicates the mainspring’s winding state per power reserve indicator on a sub-dial. A hand here usually indicates the remaining power.

The power reserve describes the maximum running time of a mechanical watch or clock after being fully wound.

It shows what state of tension the tension spring is in via a small-format round or linear sub-dial.

Highly accurate, relates to the accuracy of watches such as the chronometer.

Watch with exceptionally high accuracy. See chronometer

Mixed cut for diamond baguettes or squares, a combination of a modified step cut on the crown and a brilliant cut on the transition to the girdle.

Transfer of energy from the escapement to the timekeeping element.

Watchmaker’s tool of hardened round steel for a variety of uses. The punch is used, among other things, for driving pinions, screws and hinge pins in and out; it is used to narrow the tubes in the case of hour-hands and hour-wheels, as well as to rivet, drive together, break open and strike off parts of the movement.

The purity or fineness indicates the proportion of precious metals in their alloys in thousandths. The purity mark (hallmark) is prescribed by law for silver (minimum purity 800 thousandths), gold (minimum purity 585 thousandths) and platinum (minimum purity 950 thousandths). Bars and coins are excluded from this, as are items of jewellery that are too small to be hallmarked and historically valuable objects of precious metal.

The winding button alone is not sufficient to operate the additional functions, such as for a chronograph. Watches with additional functions are therefore provided with small pressure switches sitting to the sides of the winding button. These are referred to as pushbuttons.

Abbreviation for post meridiem (Lat. for after midday) Added to time from 12 to 24 hours in English-speaking countries.

Adjustment of the gear symmetry of a pendulum clock is referred to as beat. This is responsible for the steady ticking of a clock.

For coloured gemstones similar to those for diamonds: cut, clarity, colour, weight. Added to this is the quality criterion of whether a coloured gemstone has possibly been subjected to a chemical or physical treatment in order to improve its quality.

Term for minerals with identical or comparable chemical composition. Differentiation between macrocrystalline quartz (amethyst, aventurine, rock crystal, citrine, smoky and rose quartz, tiger’s eye), microcrystalline quartz (agate, chalcedony, chrysoprase, heliotrope, jasper, carnelian, onyx) and amorphous quartz (noble opal, fire opal).

Timepiece in which neither spring, balance nor escapement is present. In a quartz movement, a crystal (oscillator) is made to oscillate at high frequency resulting in a very high level of timekeeping accuracy. Quartz watches are either battery-powered or supplied with energy by solar cells.

Developed by Henry Grossbard in 1976. Before this date, all diamonds with straight edges (e.g. the emerald cut) had long rectangular facets. The brilliance is increased by additional brilliant cut facets below the girdle.

Radio clocks receive the exact time from an atomic clock via a time signal transmitter.

Chronograph with two overlapping chronograph hands. The second seconds hand can be stopped while the chronograph hand continues to move. The rattrapante hand is started and returned to zero simultaneously with the main chronograph hand due to the flyback function. This catching up of the chronograph hand is known by the French expression of “rattrapper” for “to catch again”.

Quartz clock without direct display, usually present in computer systems whose time measurement continues even when the device is switched off.

Gold alloy made of pure gold with a higher proportion of copper. The ratio of the material proportions affects the colour.

Specific refractive index in diamonds and coloured gemstones.

Also known as reglage, precision adjustment of a mechanical watch or clock.

Clocks with a screw balance are considered a rarity – beat errors can be corrected by turning the regulation screws on the balance wheel. This affects the clock’s precision.

Formerly widespread, particularly in grandfather clocks. The minute hand can also be designed as a single central main hand even in wristwatches. Hours and seconds are shown separately on decentralised dials.

The raised edge of a watch above the dial with additional measuring scales or stone-set border.

Final and complete inspection of the watch with its mechanism and aesthetics, just before it leaves the manufacturer.

Repeated playing of an acoustic signal in a mechanical watch by means of an elaborate complication, the repeater striking mechanism. The latter is operated by a pushpiece or a slide on the case. The most common types are: Hours, quarters and minutes repeaters.

Retrograde displays mean both retrogressively and also chronologically or locally reset or in the opposite direction, such as the retrograde weekday display: The hand for the weekday moves or jumps in the clockwise direction across a weekday scale. When the end of the scale is reached (Saturday), the hand moves or jumps back to the starting point (Sunday) on the next change of day.

Display of the seconds not centrally but on a scale with 30-second division. As soon as the hand reaches 30, it returns immediately to zero to begin again.

Thin layer applied by electroplating for surface finishing, mainly on silver to prevent oxidation (tarnishing).

Layer of rhodium applied by electroplating on silver to prevent oxidation and therefore tarnishing.

Rotatable bezel developed and patented by Rolex to interact with the movement. On the Yacht-Master II model, it affords access to the programming function of this regatta chronograph’s mechanical countdown. On the Sky-Dweller model, it allows easy selection of the function to be set: date, local time or reference time.

Case architecture designed and patented by Rolex. It enables the Rolex Deepsea divers’ watch to resist the pressure found at a depth of 3,900 meters (12,800 feet). The system is composed of three elements: a domed 5 mm-thick sapphire crystal, a high-performance nitrogen-alloyed stainless steel compression ring positioned inside the middle case, and a grade 5 titanium case back held against the middle case by a screw-down steel ring.

Pure, completely colourless and therefore transparent quartz. Was used in the Renaissance for the production of ostentatious polished vessels, nowadays also appears as a gemstone.

Combination of 904L steel and 950 platinum on the same watch. The Yacht-Master is the only Oyster model available in Rolesium. Its bezel is made of 950 platinum, while the case and bracelet are made of 904L steel.

Combination, on the same watch, of 904L steel (middle case, case back and bracelet outer links) and 18 ct gold (bezel, winding crown and bracelet centre links). The designation yellow, Everose or white Rolesor depends on whether yellow, pink or white gold is used. In the case of white Rolesor watches, only the bezel is made of gold. On Rolesor versions of the Yacht-Master, the winding crown is in 904L steel.

An extension system with a rack integrated into the clasp, developed and patented by Rolex. It enables fine adjustment of the bracelet length in 2 mm increments for a total extension of approximately 20 mm. It features on the Submariner, Submariner Date, Sea-Dweller 4000 and Rolex Deepsea divers’ watches; either with a fixed rack under the clasp cover or, for the Rolex Deepsea, in a lift-up version which allows the bracelet to be adjusted without removing the watch from the wrist.

Used as hour indicators on the dial of a clock. Other forms are bar indicators or Arabic numerals.

Gold alloy made of pure gold with proportions of silver and copper. The ratio of the material proportions affects the colour. A popular colour of gold at present for watches and jewellery.

Part of the quartz group, Mohs hardness 7. Deep or pale pink.

Rubber is originally a natural product, today it is often produced synthetically and used for hard-wearing sports watch straps.

Tourmaline variety, Mohs hardness 7 – 7.5. Predominant colours pink, red. Ruby red is very sought-after.

Part of the corundum group, Mohs hardness 9. Various shades of red, the most sought-after colour is pigeon blood red. Inclusions are considered to be natural characteristics. Due to their hardness, natural rubies were also used as bearings in watch movements. Nowadays, synthetic rubies are used for this.

Nephrite. Mohs hardness: 6 – 6.5. Tougher than jadeite. Colour: Green is the most sought-after but other colours are also possible.

Adjustable clasp of the watch bracelet, also known as a safety deployment buckle, which ensures that the watch strap does not open unintentionally but only when the pusher is operated.

All non-red varieties of the corundum group in coloured gemstone quality, Mohs hardness 9. Colours: Blue in various shades, pink, orange, yellow-green, purple. The inclusion of rutile needles characterises the star sapphire, usually cut as a cabochon.

Due to its considerable hardness, scratch-resistant watch glass of synthetic sapphire.

Caseback of scratch-resistant synthetic sapphire glass which allows the movement to be viewed.

Annual calendar mechanism developed and patented by Rolex. Its innovative design is reminiscent of the astronomical phenomenon of the same name. This mechanism allows the Sky-Dweller’s calendar to automatically differentiate between 30-day and 31-day months. The calendar thus displays the correct date throughout the year requiring only one adjustment – on 1 March, February having only 28 or 29 days.

Matte finishing of watch cases by means of metal cutting.

A special kind of matt finish. Crosswise lines are traced by hand or machine using a graver, which results in a fine matt satin-like finish.

Gold chain or rope of pearls with pearls of equal size with a length of 1 m to 1.20 m.

Standard technique in gold and silversmithing when creating jewellery. A saw frame with special metal saw blades in different thicknesses is used for sawing.

Threaded winding crown as a safety device to ensure complete water resistance of the watch case.

A crown screwed to the watch case ensures significantly higher water resistance of the watch.

Works according to the principle of the step counter. A weight which moves up and down as the watch is worn winds the mainspring via a stopwork and ensures smooth operation of the watch movement. In modern wristwatches, an improved form of this technology is now found which already functions partly as a current generator for quartz watches.

The correct term for this is precious stone (opaque, i.e. not transparent). In contrast to this: transparent coloured gemstone.

Use of different types of settings to hold gemstones, diamonds or pearls in a piece of jewellery. The following are frequently used: bezel setting, claw setting, channel setting, gipsy/flush setting, bar setting, pavé setting.

Ring shank in different design, wider or narrower with mounted setting.

Depending on the type of rough stone, it is shaped in each case by means of a suitable cut.

In watchmaking, all movements that are not round are referred to as shaped movements. These were most often used for ladies’ watches. 

Resilient bearing of the balance-staff pivot in the jewel hole and endstone ensures that shocks are absorbed. The first functional shock absorber (“Parachute”) originates from Abraham-Louis Breguet. The invention of the Incabloc system (1933) was very important for wristwatches. Today’s wristwatches are equipped with various advanced systems for shockproofing.

Also referred to as a mono-pusher chronograph. The chronograph functions are operated using only one button rather than the usual two.

To convey the precision mechanical sophistication of a movement, the plates and bridges of a movement are reduced to a functionally justifiable level to allow an unobstructed view into the complex interior. Skeleton watches often have a glass caseback and elaborate finishing (finissage). Manual skeletonising is a time-consuming and demanding craftsmanship skill with the result that these watches are predominantly found in the high price range.

Decentralized display of the seconds on the dial by means of a separate small sub-dial, which is usually positioned at 6 o’clock.

In this case, the seconds hand on the dial is not centre-mounted like the minutes and hours hands. The small seconds-hand usually has its own sub-dial.

Machine-made chain with closely set links of gold or silver.

Used when integrated in the watch case for shielding the movement from magnetism to rule out functional impairments. Particularly important for aviator watches or watches used in the physical and technical field.

Processes where two or more metal parts are combined with each other permanently through the melting and flowing of an additional metal (solder) at the joint. The solder has a much lower melting point than the metal being soldered. Unlike welding, in soldering the material at the joint is not melted. Brazing joints are very robust and are used for platinum, gold or silver jewellery.

A single stone ring for women or men in which a diamond or coloured gemstone, such as a ruby, sapphire or emerald, is individually set in the ring.

Second hand of a split-second chronograph (rattrapante) which runs concurrently with the first but can be stopped independently to measure intermediate times.

The spring is a spiral steel strip which surrounds the barrel arbor in the cylindrical case of the barrel and is attached to both the barrel arbor and also the barrel wall. The barrel arbor is turned by winding the watch by hand or automatically by the rotor and as a result the mainspring is tightened. Controlled release of the spring provides the gear train with driving power.

A spring bar consists of small tubes with sprung bearing pins which are used in wristwatches to fix the watch strap to the horns of the case.

Stainless steel is the name for alloy steel (alloyed for example with nickel, chromium or molybdenum) with particularly high corrosion resistance.

A time measuring instrument for measuring time intervals between start and stop. The operations: start, possibly intermediate stop (addition timer), stop and zero/reset take place successively.

Mechanism used mainly to permit a wheel of the movement to move in only one direction and to block its movement in the other direction.

Decorative finish for circular surfaces, used mainly on the ratchet wheel and crown wheel.

All Rolex watches are now covered by the new Superlative Chronometer certification redefined by Rolex in 2015. The certification, specific to the brand, applies to each fully assembled watch with the movement encased and is a guarantee of superlative performance on the wrist in terms of precision, power reserve, waterproofness and self-winding. The precision of a Rolex Superlative Chronometer after casing is of the order of -2/+2 seconds per day, or more than twice that required of an official chronometer. The Superlative Chronometer status is symbolized by the green seal and is coupled with an international five-year guarantee.

In watches with a sweep seconds-hand, the seconds are displayed via a hand attached in the centre of the dial. Modern movements usually have a direct sweep seconds-hand while in older movement designs the force has to be diverted by means of an indirect sweep seconds-hand.

For a watch to be labelled “Swiss made” it must meet certain requirements. Although some parts manufactured abroad may be used, according to the new tightened Swiss-ness criteria at least 60 percent of the components of a watch must be made in Switzerland. In addition, the watch must be assembled and verified in Switzerland.

Silicon hairspring with five patents, developed and manufactures by Rolex, offering singular chronometric performance for ladies’ watches. The Syloxi hairspring is paramagnetic, remains unaffected by temperature variations and exhibits a high tolerance to shocks. It employs innovative solutions that make the most of silicon technology, including an optimized geometry and an efficient design of its fixation systems.

The flat surface of a cut diamond.

Scale on stopwatches or wristwatches for measuring speed or also for other measurements such as the duration of specific operation. To determine the speed of a car, measure the time for a known distance, e.g. 1 km on the tachymeter scale. With a time of 30 seconds required for this distance, the tachymeter scale shows 120 km/h as the speed driven.

With the help of the telemeter scale, which is usually an additional scale on chronograph dials, certain distances can be measured on the basis of how long it takes sound to travel that distance. The wearer starts the chronograph at the instant the flash of lightning is seen, then stops it when thunder is heard. This value is multiplied by the sound velocity (333 m/s) and gives the measured distance in metres that can be read on the telemeter scale.

French: river; Flexible bracelet with individually set in-line diamonds of the same size and quality which are joined together in movable elements (chatons) of precious metal. In the case of coloured gemstones, there is the added feature of matched colour shades.

Braided cord of high-quality textile material (e.g. silk) which is usually worn with a pendant.

Refers to the three-quarter plate movement developed by Ferdinand Adolph Lange in the middle of the 19th century. The plate covers around three quarters of the movement and thus the whole gear train and barrel to give the movement more stability. Balance and anchor are excluded from this and are located in a cock. The three-quarter plate is also a special feature identifying high-quality watches by Glashütte.

There are a total of 24 time zones, each comprising 15 degrees of longitude and starting at the prime meridian (Greenwich). On transition from one time zone to the following time zone, the time shifts by one hour. Depending on the point of the compass, it shifts either an hour backwards (west) or forwards (east). The most important international time signals are: DCF77 (Germany) in Mainflingen in Hesse, MSF (United Kingdom) in Anthorn, JJY (Japan), WWV (USA) in Fort Collins, WWVH (USA) on Hawaii, BPC (China) in Shangqiu.

Time difference in seconds or minutes by which a clock is faster or slower than a reference clock (radio clock). The timing difference must be identical each day under exactly the same measuring conditions.

Chemical element which is one of the transition metals. Titanium is distinguished by its special strength, corrosion- and temperature-resistance with low weight and is therefore particularly suitable for processing in watch cases and watch bracelets. As titanium is practically never found in pure form, it is manufactured from titanium compounds, e.g. titanium iron ore (ilmenite) or titanium dioxide (rutile).

Barrel-like shape of a wristwatch case.

Aluminium silicate fluoride hydroxide. Mohs hardness: 8. Colour: colourless, yellow, red-brown, light blue, pale green. Despite its high degree of hardness, it is distinctly cleavable.

The tourbillon was invented by Abraham-Louis Breguet around 1800. The aim was to correct vertical position errors. The balance together with balance spring and escapement is mounted in a rotatable frame, known as the cage, and is driven by the seconds wheel sitting underneath the balance. The tourbillon (French: whirlwind) is one of the most challenging grand complications. A variation of this is the flying tourbillon, invented by Alfred Helwig in 1920. It is cantilevered, being only supported on one side.

Complex chemical and crystallographic composition. Mohs hardness: 7 – 7.5. Colours: colourless, pink, red, yellow, blue, green, purple, black or even multi-coloured. In terms of colour, the tourmaline varieties are distinguished as follows: achroite: colourless to almost colourless, dravite: yellow-brown to dark brown, indicolite: blue in all shades, rubellite: pink to ruby red, siberite: lilac red, violet blue and verdelite: every shade of green.

Quality characteristic of coloured gemstones as good transparency also determines the value.

Combination on the same watch of 18 ct yellow, white and Everose gold for the bracelet links.

Screw-down winding crown with a triple waterproofness system developed by Rolex for its divers‘ watches, now fitted on a number of Professional models. Identified by three dots below the Rolex emblem, it ensures waterproofness to a depth ranging from 100 to 3,900 metres (330 to 12,800 feet) depending on the case.

Scew-down winding crown with a double waterproofness system developed by Rolex ensuring waterproofness to a depth of 100 metres (330 feet). Identified by two dots (gold winding crown), one dot (platinum winding crown) or a line (steel winding crown) below the Rolex emblem.

The first barrel serves as the energy supplier for the normal functions of a watch, the second for energy-intensive additional complications.

For cleaning pieces of jewellery made of precious metal. Caution is required for some sensitive coloured gemstones.

Collective term for all the parts, such as musical, repeating, striking and chronograph mechanisms, mounted between the dial and the dial plate.

A rotating ring attached on the upper side of the case for adjusting special functions (GMT display, dive time, tachymeter scale). Moves only in a counter-clockwise direction to prevent adjustment or reading errors.

Sub-types of a group of coloured gemstones (e.g. quartz varieties) or also their colour differences.

Machine-made version of the anchor chain with flat, mobile chain links.

Movement limited by two consecutive extreme positions. In mechanical watches, the number of vibrations per hour is often shown instead of the oscillation frequency. The balance of a mechanical watch, for example, makes eight vibrations per second, that is 28,800 beats per hour.

This certificate is issued exclusively for the Wagner Juwelen Design collections, identified by the blue Wagner sapphire, and the diamonds and precious stones used in these collections. A certificate is issued for each item of jewellery with the number and carat details of the precious stones. The certificate covers the following criteria: type of precious metal in the jewellery, type of precious stone, carat, clarity and colour scale.

Watches whose basic movement is coupled to with cadratures/under-dial work (sometimes modular additional mechanisms). These include moon phase display, full calendar (also known as annual calendar), perpetual calendar, date display, large date, jumping date change, retrograde displays, rattrapante, alarm, minute repeater or the display of several time zones (GMT function).

Device for keeping automatic watches moving when they are not being worn and thus wind them up.

Watchmakers develop watches, build and service them. However, the majority of the watchmaker’s professional career is spent on the care and maintenance of watches. The watchmaker’s profession is one of those skilled trades which in fine watchmaking, i.e. in the case of grand complications, also requires great craftsmanship.

The details regarding the water resistance of watches repeatedly lead to misunderstandings as the information in metres is misleading. The water resistance is correctly stated in bar rather than metres, i.e. 3 bar = 30 m/5 bar = 50 m/10 bar = 100 m/20 bar = 200 m.

Ring worn as a clearly visible sign of a marriage between both partners. Wedding rings are usually made in 18 ct gold or platinum, they are not set with stones or a claw set stone (solitaire).

Is specified in carats (ct) for coloured gemstones and also diamonds. One carat is equivalent to 0.2 grammes.

Chain with hollow chain links which are soldered together in pairs in a twisted form.

Gold alloy made of pure gold with the addition of palladium (French: or gris). The ratio of the material proportions affects the colour.

Development by Louis Audemars (around 1837) and Adrien Philippe (around 1845). By turning the crown which sits on top of the winding stem, the mainspring is wound via the ratchet wheel and crown wheel as well as the winding pinion. The watch hands can also be adjusted by pulling the winding stem out slightly. The winding crown replaced the older winding key.

The connection to the movement can be created by turning the winding button sitting on the end of a watch’s winding stem. A small gear mechanism is responsible for functions such as winding the movement, adjusting the hands or date.

Greenwich Mean Time (GMT) set on Greenwich as the prime meridian during the Washington Meridian Conference 1884 and therefore the first universally valid world time instead of local times. It has been referred to as Universal Time (UT) since 1928. The Coordinated Universal Time (UTC), represented by atomic clocks, has been used as world time since 1972. In everyday life, the relevant time zone is applicable; in international traffic, such as air traffic, universal time applies.

Developed out of the pocket watch from around 1900 and supplanted it due to better wear comfort and usability.

X-ray fluorescence analysis for analysing coloured gemstones or pearls.

Yellow gold alloy of fine gold with silver and copper content. The ratio of the material proportions affects the colour.

The resetting of a chronograph hand to 12 o’clock after the time measurement is complete by pressing the pushbutton.

Movement already fitted with stems and gear wheels but still without escapement.

Unit of measurement for the purity of gold. 58.5 percent of pure gold (585/1000), to which silver and copper may be added as pure gold is too soft for jewellery making or watch cases. The colour of gold depends on the type and proportion of these alloys. The appropriate precious metal hallmark is mandatory and guarantees the purity.

Unit of measurement for the purity of gold. 75.0 percent of pure gold (750/1000), added to which may be silver and copper as pure gold is too soft for jewellery making or watch cases. The colour of gold depends on the type and proportion of these alloys. The appropriate precious metal hallmark is mandatory and guarantees the purity.

Unit of measurement for the purity of gold. 91.67 percent of pure gold (916/1000), mainly used for gold coins. Commonly used in England, South Africa, Arab countries, India. The precious metal hallmark guarantees the purity.

A stainless steel alloy extremely resistant to corrosion and often used in the aerospace and chemical industries. In 1985, Rolex pioneered the use of 904L steel for the cases of all its steel watches. The anti-corrosion properties of 904L steel are comparable to those of precious metals, and its purity ensures high polishing quality. 904L steel therefore offers the finest lustre as well as extreme durability.