Gold & Gold Cap
Fine gold in its pure state (24 karats) is a highly malleable metal that is not easy to finish (polish). It must therefore be alloyed with other metals to enhance its properties and enable its transformation for use in jewellery and watchmaking.
Longines uses 18-karat gold (an alloy of gold, silver and copper), ideal for manufacturing its watches.
COLORS :
The colour varies according to the percentage of alloys used.
- Yellow gold (known as 2N): 75% gold, 16% silver, 9% copper
- Rose gold (known as 5N): 75% gold, 5% silver, 20% copper
HALLMARKS
A solid-gold watch will always have official hallmarks affixed by the Swiss Federal Body for Precious Metals Control (CMP) including
- "Head of a Saint-Bernard", the Swiss assay mark
- Scales and 750 [18 K gold], common (international) hallmark
- Inscription Au 750 [18 K gold], standard of fineness
These are applied to the back but are valid for the entire watch head, because the law recognises that the back of a watch is difficult to remove without special tools.
ADVANTAGES:
Precious, elegant, timeless and hypoallergenic, gold is also an investment.
USE:
Case (case middle, bezel, back, crown, push-buttons), bracelet.
HOW CAN THE GOLD ON A LONGINES TIMEPIECE BE IDENTIFIED?
1. STANDARD OF FINENESS
The fineness guarantees the proportion of precious metal in an alloy. It is expressed in thousandths, for example 750/1000, and for gold it is also expressed in karats, i.e. 18 karats, where 24 karats represents pure gold.
2. MANUFACTURER'S LOGO
For example, the hammer is the "Collective Responsibility Mark" of manufacturers of watch cases in the Jura.
3. SWISS ASSAY MARK
Every watch case made of gold, silver, platinum or palladium sold in Switzerland has to be officially assayed and hallmarked. A single official hallmark was adopted in 1995: the "Head of a Saint-Bernard".
4. COMMON CONTROL MARK
Hallmark of the multilateral convention on the control and hallmarking of objects made of precious metals (Vienna Convention).
SOLID GOLD CROWN
The crown is considered to be part of the movement, not the case. As a result, the case back bears the appropriate marking "ALL STAINLESS STEEL".
