Jewelry items made from precious metals are stamped with purity mark or seal to indicate the purity level of the metal composition. This stamp is usually in a hidden place on the item so it does not interfere with the design or appearance of the jewelry. Because of this you can find them on the inside of wedding band rings, on the back of a pendant or on the post of an earring. The Federal Trade Commission sets strict guidelines and regulations for all jewelry stamps. Common jewelry metal stamps are used to identify metals, trade marks, designer or manufacturer.
Note that colored golds (White, Red/Rose, etc.) can only have a maximum purity of 22 karats due to the alloys introduced into the gold to create their color. There is no such thing as 24k White gold or 24k Rose gold.
The table below list precious metal stamps, their meaning and purity level.
| Metal Stamp | Meaning |
| 10k | 10 parts out of 24 Yellow/White Gold |
| .417 | 10 parts out of 24 Yellow/White Gold |
| 14k | 14 parts out of 24 Yellow/White Gold |
| .585 | 14 parts out of 24 Yellow/White Gold |
| 18k | 18 parts out of 24 Yellow/White Gold |
| .750 | 18 parts out of 24 Yellow/White Gold |
| 20k | 20 parts out of 24 Yellow/White Gold |
| .833 | 20 parts out of 24 Yellow/White Gold |
| 22k | 22 parts out of 24 Yellow/White Gold, max possible for colored golds |
| .900 | 22 parts out of 24 Yellow/White Gold, max possible for colored golds |
| 24k | 24 parts out of 24 Yellow gold |
| .999 | 24 parts out of 24 Yellow Gold |
| PLAT | Platinum |
| PT | Platinum |
| 900 | Platinum |
| 950 | Platinum |
| S.S. | Stainless Steel |
| Steel | Stainless Steel |
| STER | Sterling Silver |
| Silver | Sterling Silver |
| Sterling Silver | Sterling Silver |
| .925 | Sterling Silver |
| Titanium | Titanium |
| Tungsten | Tungsten |
| Pd | Palladium |
Gold Filled and Gold Bonded Jewelry
There is a separate stamping regime for jewelry that is `Gold Filled`. To learn more about Gold Filled jewelery
read our gold metal guide, but essentially gold filled jewelry is gold bonded to an inferior metal, much like gold plating. The United States Federal Trade Commission requires all gold filled jewelry to use at least 10 karat quality gold, and that the bare minimum for 10 karat gold is that the gold makes up 1/10 of the total weight of the product. In turn, the 12 and 14 karat gold content of a gold filled product must be 1/20. This is why you will see stamps like `1/10 10k GF` on various gold filled or bonded gold products. Here is an approximate list of the applicable stamps and markings, but since there are several possible combinations it may not be possible to easily describe them all:
| Metal Stamp | Meaning |
| 1/10 10k GF | 1/10th of the weight of the product is 10 karat gold |
| 1/10 12k GF | 1/10th of the weight of the product is 12 karat gold |
| 1/20 12k GF | 1/20th of the weight of the product is 12 karat gold |
| 1/20 14k | 1/20th of the weight of the product is 14 karat gold |
The FTC also allows gold filled products to market themselves at less than `1/10 10k GF` but requires a different designation. Products that that are composed of 12 karat gold for example, wherein the gold is less than 1/60 of the total product weight, can be marked as `1/60 12kt RGP`. The RGP stands for `Rolled Gold Plate`, and will wear down or start to show the base underlying metal sooner than `GF` graded products. Basically a RGP product is the same as a GF product above, but with an even thinner layer of gold used.