1. Jewelry Identifier
  2. Hallmarks
  3. 1/10 12K GF

* gold-filled hallmark

The 1/10 12K GF hallmark: meaning, purity & value

Gold filled with 12K layer making up 1/10 (10%) of total weight. Higher gold content than typical 1/20 GF; common on older American costume pieces.

Published May 30, 2026

Quick facts

Metal
gold-filled
Common regions
United States

Stamps that mean the same thing

This purity may be struck into jewelry as any of: 1/10 12K GF / 12K GF / 1/10 12kt GF. The mark differs by country and era, but the metal content is identical.

What 1/10 12K GF tells you

Gold filled with 12K layer making up 1/10 (10%) of total weight. Higher gold content than typical 1/20 GF; common on older American costume pieces.

How to check it yourself

  1. Examine the stamp under a 10× loupe — genuine marks are crisp and evenly struck, not doubled or smeared.
  2. Confirm the mark reads 1/10 12K GF or an equivalent such as 12K GF.
  3. Photograph it in the Jewelry Identifier app to read the metal, hallmark, and any gemstones from the image.
  4. For a binding result, have an assay office or gemological lab run an XRF purity test.

Sources

* Frequently asked

FAQ

Q. Is 1/10 12K GF the same as 12K GF?
A. Yes. 1/10 12K GF, 12K GF, 1/10 12kt GF all denote the same material — gold-filled. Different markets and eras stamp it differently, but the purity is identical.
Q. How do I confirm a 1/10 12K GF stamp is genuine?
A. Look at the mark under 10× magnification for crisp, even strikes, cross-check the weight-to-volume ratio against the expected density, scan it with the Jewelry Identifier app, and — when it matters — have an XRF test done by an assay office or gemological lab.

* Try it

Identify the jewelry in your hand, right now.

Just take a photo — AI reads the metal, gemstone, hallmark, era, and an estimated value range in seconds. First two scans free, no account required.

Download on the App Store

* Related

Keep exploring