Karat

For a hands-on guide to gold purity and how to check it at home, read our article on gold purity, fineness and karat. This entry covers the karat scale and what it means when you compare jewelry with bullion.

Karat to fineness conversion

To convert karats into percent, divide by 24. In the US the word is spelled karat, while carat with a "c" measures the weight of gemstones. The same purity can also be written as fineness.

US rules: why 10k is the floor

The FTC Jewelry Guides (16 CFR Part 23) say it may be misleading to call an item gold, or mark it with a karat stamp, if it is made of an alloy below 10 karat. That is why you see 10k, 14k and 18k in American stores, while 9k is common in Britain. The National Gold and Silver Stamping Act adds that a karat mark must be accurate and must sit next to the maker's registered trademark.

Gold-filled and gold-plated are not karat gold

"14k gold-filled" (GF) or "gold-plated" means only a thin layer of karat gold over a base metal. These pieces have little melt value and dealers rarely buy them by weight.

Jewelry vs bullion: what you pay for

Karat tells you how much gold you hold, not what it is worth to a buyer. Example with fixed numbers: a 14k chain weighing 20 g contains 20 x 0.583 = 11.67 g of pure gold, or 0.375 troy ounce. A 1/2 oz gold coin holds 0.5 oz. The chain may have cost far more at retail because of design and labor, but a buyer will pay only for gold content, minus a margin.

Bullion works the other way around. A 22k Gold Eagle and a 24k Buffalo both contain one full ounce, and their prices follow the spot price closely. If your goal is metal rather than jewelry, compare the American Eagle gold coin prices or the Buffalo gold coin offers. To estimate scrap value of old jewelry, use the gold melt value calculator with the karat and weight in grams.

Note that the spread on jewelry sold for scrap is usually much wider than on bullion coins, because the buyer has to refine it.