One of the great qualities of gold is its malleability. This, combined with its physical beauty and resistance to corrosion, makes gold the ultimate creative medium. Pure gold can be considered too soft and delicate for use in jewellery, so it is often combined with other metals for greater strength.
The term caratage simply refers to the proportion of pure gold in a piece of jewellery. Caratage can be defined in two ways:
- as ‘fineness’ which expresses the amount of gold in parts out of 1000;
- as a ‘percentage’ of pure gold
For convenience, you’ll find both measures indicated in the chart below.
|Carats||Fineness (of 1000)||Gold, % content||Comments|
|24||990||99.0%||Minimum allowed for pure gold jewellery. Popular in China|
|22||916||91.6%||Popular in India|
|21||875||87.5%||Popular in Middle East|
|19.2||800||80.0%||Standard in Portugal|
|18||750||75.0%||Standard international caratage|
|14||585||58.5%||583/58.3% in US|
24 carat gold is pure gold in its refined state. It is soft, flexible, and even delicate. This is a popular caratage for jewellery in China, especially for the wedding ceremony itself.
22 and 21 carat gold is made of 91% and 87% pure gold respectively. These caratages are particularly prevalent in India and the Middle East.
18 carat gold has become an international standard for jewellery, containing 75% pure gold. Combining purity with performance, 18 carat gold has, for example, been adopted as the caratage of choice for the world’s leading watch brands. In addition, this is the caratage at which gold can magically begin to change colour as other metals are added to the alloy.
It is possible to make gold jewellery below 18 carat. In the US, 14 carat (or karat) is also widespread, but gold of a caratage under 10 carat is illegal in this market and cannot be sold as gold.
9 carat gold is a common caratage in the UK; its introduction actually dates from wartime when the UK government allowed assay offices to create this lower caratage in order to maintain production of wedding bands which were classified as “essential items” throughout the war itself.
In many countries, local law requires that every item of gold jewellery bears a clear stamp indicating its caratage. This identification is often controlled through a hallmarking system, which originated in 14th century London at Goldsmiths' Hall. Today, hallmarking is compulsory in such countries as Britain, France, the Netherlands, Morocco, Egypt, and Bahrain.
Where there is no compulsory marking, manufacturers usually stamp the jewellery themselves, displaying both their own identifying mark and the caratage or ‘fineness’ of each piece.