Argand burner

An oil lamp once used by watchmakers as lighting.

Bolt

A catch that can be operated from the outside of a watch case to trigger a mechanism, for example to set the hands.

Cut

Cut is the result of centuries of research, trial and error. A stone is cut to show off its colour and create lustre by the play of light on its facets and eliminating its defects. Diamonds are...

Date

The number, in order, of each day in the month.

Exterior

The different parts (case, dial, hands, crystal, crown, etc.) that help to give the watch its finished and functional appearance.

Feuille

A hand in the form of a leaf.

Grande sonnerie

Watch that strikes the hours and quarters in passing and repeats the hour at each quarter. The hour and quarter strikes can be repeated on demand. Certain Grande Sonnerie...

Hematite

A natural iron oxide that is a metallic dark to silver-grey with a high sheen. Hematite can be used to make watch dials. It has a specific gravity of 4.95 to 5.16 and a hardness of 6.5 on the...

Isochronism

The property of being isochronal.The science of timing lies in achieving isochronism of the regulating organ of a timekeeping instrument. The principal factors that can impair a balance's...

Jumping seconds

On a chronograph, a hand that makes one rotation every second, pausing four, five, even eight times to indicate quarters, fifths or eighths of a second. Also called foudroyante.

Karrusel

A device similar to the tourbillon, the difference being that the cage is driven by the third wheel. Invented by Bonnicksen, a Danish watchmaker established in London.See complication.

Lapis lazuli

A rich blue opaque gemstone often used in watch dials. It is specked with pyrite that looks like gold. Lapis has a hardness of 5.5; it has a specific gravity of 2.4 to 2.9. Lapis lazuli is not a...

Movement

The duly-assembled organs and mechanisms of a watch, meaning the winding and hand-setting mechanism, the mainspring, the gears, the escapement and the regulating organ (spring...

Nephrite

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

Piezoelectric

The ability of certain crystals to generate a voltage in response to applied mechanical stress (pressure, twisting, traction, etc.). Discovered by brothers Pierre and Jacques Curie in...

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...

Resonance

This sophisticated technique, developed by Breguet and applied to wristwatches by François-Paul Journe, implies two fully independent movements: two mainsprings, two geartrains, two lever...

Stopwork

System that controls tension to the mainspring when wound. The best-known stopwork mechanism is the "Maltese cross".

Tourmaline

A dichroic gemstone that comes in all colours of the rainbow. Some crystals are bi or tri coloured. Tourmaline has the greatest colour range of any gemstone. Tourmaline has a hardness of 7-7.5 and...

Ultra-complicated watch

Any function other than the indication of hours, minutes and seconds, regardless of whether the mechanism is hand-wound or self-winding, mechanical or electronic, and of movement height. The...

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.

Zodiac

At the heart of countless legends and beliefs, since ancient times precious stones have had symbolic value. From the Jews to the Egyptians, each culture and religion has given a different meaning...