Fineness
Metal purity expressed in parts per thousand, such as 916 for 22K gold or 750 for 18K gold.
Fineness is purity written as a number out of a thousand. Where karat divides gold into 24 parts, fineness divides it into 1000, so 916 means 91.6 percent gold and 750 means 75 percent. It is the numeric form of purity you see stamped in hallmarks, sometimes alongside a karat mark and sometimes instead of one, and the same parts per thousand system is used for silver and platinum too.
Reading fineness numbers
The number is simply the pure metal content per thousand parts. 999 is 99.9 percent pure, the fineness of 24K gold. 916 is 91.6 percent, which is 22K. 750 is 75 percent, which is 18K, and 585 is about 58.5 percent, which is 14K. To convert from karat, divide by 24 and multiply by 1000.
Fineness appears on hallmarks precisely because it is unambiguous. A stamp reading 750 states the purity directly as a number, which is why modern hallmarking schemes such as India's BIS use the fineness grade as one of their core marks.
- 999 fineness equals 24K, 99.9 percent gold.
- 916 fineness equals 22K, 91.6 percent gold.
- 750 fineness equals 18K, 75 percent gold.
- 585 fineness equals 14K, about 58.5 percent gold.
Fineness across metals
The parts per thousand system is not limited to gold. Sterling silver is 925 fineness, meaning 92.5 percent silver, and platinum jewellery is often 950, meaning 95 percent platinum and marked Pt950. The same logic applies: the number is the share of pure metal per thousand.
For pricing, fineness is effectively the purity fraction scaled up by a thousand. Divide the fineness by 1000 to get the decimal, so 916 becomes 0.916, then multiply by weight and rate to get the metal value. It is the same calculation whether the mark shows karat or fineness.
- Fineness is purity in parts per thousand.
- 916 is 22K, 750 is 18K, 585 is 14K, 999 is 24K.
- It is used on hallmarks as an exact purity number.
- The same system applies to silver, such as 925, and platinum, such as 950.
Fineness, in short.
What does 916 fineness mean?
It means the metal is 91.6 percent pure gold, the parts per thousand form of 22K. Divide 916 by 1000 to get the decimal purity fraction of 0.916.
How is fineness different from karat?
They express the same purity differently. Karat is out of 24, fineness is out of 1000. 18K and 750 describe identical metal that is 75 percent gold.
Related terms
See fineness inside a real jewellery system.
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