One of the most popular classifications of gold is based on carats. Incidentally, carat measures the purity of gold and higher the carat value, higher is the purity of gold. Broadly, gold has 5 popular classifications based on purity, which is captured as under.
| Particulars | 24-Carat | 22-Carat | 18-Carat | 14-Carat | 10-Carat |
| Gold Purity | 99.95% | 91.67% | 75.00% | 58.33% | 41.67% |
Higher the purity, more malleable and softer will be the gold. Hence 24-carat gold is rarely used for jewellery as daily wear and tear will make it lose shape. The most popular for gold jewellery is 22-carat gold which has 91.67% purity. However, even 22-carat gold cannot hold diamonds and studded gems. Hence for jewellery with studded stones or diamonds, normally lower purity gold of 18-carat or 14-carat is used. Lower carat gold consists of a mix of gold with silver, nickel and zinc.