Updated
10K means 10 karat gold: 10 parts gold in 24, or 41.7% pure. On its own, the stamp marks solid gold.
10K, 10KT, 10 KARAT, and 417, the European way of writing it.
Class rings, men's rings and lower-priced chains. In the US, 10K is the lowest karat usually sold as gold. Older 10K rings are often marked 10K HGE or 1/10 10K GF, and those letters mean a gold layer, not solid gold.
10K on its own means solid gold. The same number followed by letters means a layer of 10K gold over another metal, which holds far less gold:
| Stamp | What it means | Gold, 5 g ring |
|---|---|---|
10K | Solid 10K gold all the way through | 2.08 g $271.86 |
1/20 10K GF | Gold filled: a bonded layer of at least 10K gold, at least 1/20 of the total weight | 0.10 g $13.59 |
1/40 10K RGP | Rolled gold plate: a bonded layer, at least 1/40 of the total weight | 0.05 g $6.80 |
10K HGE | Heavy gold electroplate: at least 2.5 microns of gold | about $2.52 |
10K GEP10K GP | Gold electroplate or gold plate: at least 0.175 microns of gold | about $0.18 |
Pure gold content at today's $130.39 a gram. Plated rows assume a plain ring with about 4 square centimeters of surface at the FTC minimum thickness (16 CFR 23.3).
Melt value = weight in grams × purity × spot price per gram
Spot prices are quoted per troy ounce, and a troy ounce is 31.1035 grams. Gold spot is $4,055.57, so pure gold is $130.39 a gram.
5 grams of 10K gold: 5 × 0.417 × $130.39 = $271.86
Weigh it in grams on a kitchen or jewelry scale. Set stones add weight, so the true figure is a little lower. A buyer pays less than melt to cover refining and profit. Melt value calculator
Photograph it, then take a close-up of the stamp. GemstoneAI uses a legible stamp for the metal and gives a first read on what you have and what it may be worth. Your first scan is free.
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A stamp is a claim, not proof. Fake jewelry is sometimes stamped with real-looking marks. In the US, a purity mark is supposed to sit next to a maker's trademark, so a purity stamp on its own deserves a closer look.
More checks: how to tell if gold is real and the 5-question ring checker.
Yes, when 10K stands alone or beside a maker's mark. It is real gold, just less of it than 14K or 18K. 10K followed by GP, HGE, RGP or GF means a gold layer over another metal.
Yes. 10K and 417 both mark 10 karat gold, about 41.7% pure.
About $54.37 per gram at melt today.