Is 18KGF the same as 18K Gold Filled?

Yes. 18KGF, 18K Gold Filled all denote the same material — gold-filled. Different markets and eras stamp it differently, but the purity is identical.

How do I confirm a 18KGF stamp is genuine?

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.

* Gold-Filled hallmark

The 18KGF hallmark: meaning, purity & value

18KGF is 18K gold-filled. Higher gold content in the bonded layer than 14KGF, still not solid 18K for scrap.

Published May 30, 2026

Quick facts

Metal: Gold-Filled
Common regions: United States, Japan
Standard: ISO 9202

Stamps that mean the same thing

This purity may be struck into jewelry as any of: 18KGF / 18K Gold Filled. The mark differs by country and era, but the metal content is identical.

What 18KGF tells you

18KGF is 18K gold-filled. Higher gold content in the bonded layer than 14KGF, still not solid 18K for scrap.

How to check it yourself

Examine the stamp under a 10× loupe — genuine marks are crisp and evenly struck, not doubled or smeared.
Confirm the mark reads 18KGF or an equivalent such as 18K Gold Filled.
Photograph it in the Jewelry Identifier app to read the metal, hallmark, and any gemstones from the image.
For a binding result, have an assay office or gemological lab run an XRF purity test.

Sources

ISO 9202
Trade hallmark references

* Frequently asked

FAQ

Q. Is 18KGF the same as 18K Gold Filled?: A. Yes. 18KGF, 18K Gold Filled 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 18KGF 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.

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