Guide
What Are Carat and Millesimal Fineness?
Carat expresses the purity of gold out of 24; millesimal fineness expresses the same purity out of 1000. A 14-carat ring is stamped 585: 585 grams of every thousand are pure gold.
Carat to fineness
| Carat | Fineness | Pure gold | Common use |
|---|---|---|---|
| 24 carat | 995 – 999 | 99.5% – 99.9% | Bullion and gram gold (investment) |
| 22 carat | 916 | 91.6% | Bangles, ornamental gold, coins |
| 18 carat | 750 | 75.0% | Diamond and fine jewellery settings |
| 14 carat | 585 | 58.5% | Everyday jewellery: rings, earrings, necklaces |
| 8 carat | 333 | 33.3% | Light jewellery, export pieces |
Why isn't jewellery made from pure gold?
Pure 24-carat gold is soft; in daily wear it scratches and loses its shape. Alloyed with copper, silver or zinc it becomes durable — and its colour changes. The difference between yellow, white and rose gold comes from these alloy ratios.
Working out the fineness
Fineness = carat ÷ 24 × 1000. For 18 carat: 18 ÷ 24 × 1000 = 750. The pure gold inside a piece is grams × fineness ÷ 1000: a 10-gram 14-carat bangle contains 10 × 585 ÷ 1000 = 5.85 grams of pure gold.
What sets the price?
The price of a piece is not only the pure gold inside it. Alongside weight, fineness and the day's gold rate, workmanship is part of the price. In crafted jewellery the workmanship share is high; in investment gold it is close to nil.