The karat (k) as applied to gold denotes its degree of purity — not to be confused with the carat (ct) of gemstones, which is a unit of weight.
Pure Gold: 24 Karats
24-carat gold (24k) is 100% pure gold. This metal is of absolute beauty and exceptional malleability — one ounce of pure gold can be beaten into a sheet covering 100 square feet, or drawn into a wire 50 miles long. But this very malleability is also its weakness: too soft for jewellery, a 24k gold piece would quickly deform and would not hold stones with the necessary security.
18-Carat Gold: The Choice of Fine Jewellery
18-carat gold (18k, 750/1000) is composed of 75% pure gold and 25% other metals forming the alloy. It is the standard of French fine jewellery for generations — the one we use at Origine Paris.
This alloy combines the best of both worlds: the purity and lustre of 75% gold, with the resilience and strength needed to create durable jewels that hold diamonds with precision. In France, 18-carat gold jewellery is identifiable by the eagle head hallmark.
14-Carat and 9-Carat Gold
14-carat gold (585/1000) contains 58.5% pure gold. It is less expensive than 18-carat and very common in Anglo-Saxon countries. 9-carat gold (375/1000) contains 37.5% pure gold and is mainly used in mass-market jewellery.
One Karat, 1/24th
The karat is divided into 24 parts. An 18-carat gold piece contains 18/24 pure gold, i.e. 75%. For a 24-gram piece of jewellery, this means 18 grams of pure gold and 6 grams of other metals. These metals vary according to the desired colour — silver, copper, palladium — to obtain yellow, white or rose gold.