Arabic numerals

1, 2, 3, etc. Arabic numerals, which were widely used on watch dials towards the eighteenth century, allow greater scope for fantasy than their Roman counterparts. The majority of fine-quality...

Birefringence

The property of all stones, except those of the cubic crystal system (diamond, garnet and spinel), to divide a passing ray of light in two. Also known as double refraction.

Corrector

A button flush with the case middle used for adjusting the different indications, such as the date, by means of a special tool.

Demantoid garnet

A valuable yellowish green, very lustrous and rare variety of the garnet group.

Electroplating

A plating technique using electrodeposition.

Fancy diamonds

Rare diamonds which are naturally red, blue, green, or purple. Their price mainly depends on the saturation and quality of colour.

Gears

A set of wheels and pinions whereby the movement of one sets all the others in motion.There are different types of gears, e.g. winding gears, strike-train, etc.

Hand

A variously shaped indicator made from a thin piece of lightweight metal and which moves round a dial, with or without graduations. Most watches have three hands, one each for the hours, minutes...

Impulse

In a lever escapement, the action of the escape-wheel tooth on the impulse-face of the pallet.

Jade

Jade is a gem group with jadeite and nephrite as the two varieties. Jadeite is the variety that ranges in colour from green to white to lilac to brown to almost black. Nephrite, the more ancient...

Kunzite

A transparent pink or light purple gemstone and is a variety of spodumene. The colour of some kunzite can be enhanced by irradiation. Kunzite has a hardness of 6-7 and a specific gravity of 3.1 -...

Lathe

A machine-tool that rotates a workpiece while applying a cutting tool to give the piece the required shape. The lathe, with its multiple accessories, is the traditional watchmaker's most versatile...

Manufacture

The Swiss watch industry uses this term to differentiate between a company that manufactures a watch almost in its entirety as opposed to finishing shops which only assemble and time the watch,...

Nephrite

A family of the jade group of ornamental gemstones. Nephrite is slightly softer that jadeite and is often veined.

Ornamental gems

Any microcrystalline gemstone. Some examples are: Agate, Onyx, Sodalite, Malachite, etc. These ornamental stones are mostly used for watch dials.

Pavilion

In a cut stone, the part below the girdle (for diamonds) or rondiste (for coloured stones).

Quartz

Silicon dioxide. Also called rock crystal. Quartz has the specific property of vibrating at a very high frequency (32 MHz) placed under electric current. Under certain conditions, it...

Swiss T 25 (T Swiss made)

So that watches (and timekeeping devices in general) can be read in the dark, the numerals, hour markers and hands must be coated with a luminescent substance. As a general rule, the light emitted...

Time zone

In order to standardise time measurement in each country, since 1883 the Earth has been divided into twenty-four time zones, the first of which is intersected by the Greenwich meridian,...

Universal (watch with universal hours)

A watch whose dial shows the time of places in different time zones.

Vagues de Genève

Synonym of Côtes de Genève. A decoration of undulating lines, like waves, frequently used to embellish superior quality movements.

Water-Resistant

Describes a watch which, in theory, will not let in water at a depth of up to 3 atm or 30 metres. See Waterproof

Year

A four-digit indication of the current year that changes automatically at midnight on December 31st.

Zinc

A metal applied by electrodeposition (electroplating) to protect iron and steel.