Fineness is the share of pure metal in a coin or bar, written in parts per thousand. A gold bar marked .9999 is 99.99% gold; a coin marked .900 is 90% silver or gold.
For a hands-on guide to gold purity, karat and how to check them at home, read our article on gold purity, fineness and karat. This entry explains how fineness is written on bullion and what it means for price.
How fineness is written
Fineness counts parts of pure metal per thousand. US dealers usually write it as a decimal: .999 ("three nines"), .9999 ("four nines") or .9167 for 22 karat gold. Jewelry uses karats instead, but both describe the same thing.
| Fineness | Pure metal | Typical US products |
|---|---|---|
| .9999 | 99.99% | American Gold Buffalo, Maple Leaf, most gold bars |
| .999 | 99.9% | American Silver Eagle, silver rounds and bars |
| .995 | 99.5% | Minimum gold fineness for COMEX delivery bars |
| .9167 | 91.67% | American Gold Eagle, Krugerrand (22 karat) |
| .900 | 90% | Pre-1965 dimes, quarters and half dollars |
Who guarantees fineness in the US
The US has no government assay office that hallmarks every bar, as some countries do. Fineness rests on three things:
- The issuer. US Mint coins carry a federal guarantee of metal content and weight.
- Federal marking law. The National Gold and Silver Stamping Act (15 U.S.C. § 291 and following) makes it unlawful to sell items marked with a higher fineness than they contain. For gold, § 295 allows the actual fineness to fall short of the mark by no more than three thousandths. Anyone who applies a quality mark must also apply a registered trademark or name next to it (§ 297).
- The refiner. Bars from refiners on the LBMA list or COMEX-approved brands follow strict assay rules.
Why .995 gold and .999 silver matter for IRAs
Under 26 U.S.C. § 408(m)(3) an IRA may hold bullion only if its fineness is at least the minimum a regulated futures market requires for delivery. COMEX gold futures require gold of at least 995 fineness, which is why custodians accept .995 gold and .999 silver. The American Gold Eagle is the well-known exception: at .9167 it is below .995, but the law names American Eagle coins directly, so they are IRA-eligible anyway.
Constitutional silver: 90% coins
Dimes, quarters and half dollars dated 1964 or earlier are 90% silver and 10% copper. The Coinage Act of 1965 replaced that alloy with copper-nickel clad metal. Collectors call these coins "junk silver" or constitutional silver. A pre-1965 quarter weighs 6.25 g, so it holds 5.625 g of pure silver (6.25 x 0.900), or 0.1808 troy oz. Check any coin with the silver melt value calculator, or for gold the gold melt value tool.
Higher fineness does not mean more gold per coin. A 1 oz Eagle and a 1 oz Buffalo hold the same troy ounce of gold. Compare them in the gold coin price comparison by price per ounce, not by purity.
Related terms
Karat Troy Ounce LBMA Good Delivery Precious Metals Sales Tax
FAQ
What does .9999 mean on gold?
It means the bar or coin is 99.99% pure gold, also called four nines or 24 karat.
What fineness is required for a gold IRA?
Bullion must meet the fineness accepted for delivery on a regulated futures market, which in practice is .995 for gold and .999 for silver, with American Eagle coins allowed by name.
How much silver is in pre-1965 coins?
US dimes, quarters and half dollars dated 1964 or earlier are 90% silver, so $1 face value of unworn dimes holds about 0.723 troy ounces.