What is fineness in precious metals?
By Jared James · Last updated 21 May 2026
Definition
Fineness measures how much precious metal is in an alloy, expressed as parts per thousand. A piece stamped 750 is 750 parts per thousand pure gold, which equals 18ct or 75%. A stamp of 585 denotes 14ct gold at 58.5%, and 375 means 9ct at 37.5%. Silver uses the same system: 925 is sterling silver at 92.5% purity. The fineness mark is the number you will see hallmarked onto gold and silver jewellery worldwide, giving a precise purity statement that the karat label summarises.
Frequently asked questions
- How does fineness relate to karat?
- Karat is the scale used in the United States and some other countries, running from 1 to 24, while fineness expresses the same information as a number out of 1000. 18ct gold is 750 fineness (750/1000 = 75%), and 9ct gold is 375 fineness (37.5%).
- What fineness marks will I see on jewellery in Australia?
- Australian jewellery commonly carries fineness stamps of 375 for 9ct gold, 585 for 14ct, 750 for 18ct, and 999 or 925 for silver. Some older or imported pieces use the karat or carat notation instead.
- Why does fineness matter when buying jewellery?
- It tells you exactly what you are getting. A higher fineness in gold means more pure gold content, which affects colour, price and how the metal behaves with sensitive skin. It also matters for resale, because bullion and precious metal recovery values are based on fineness.
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