* gold-filled hallmark
The 1/30 hallmark: meaning, purity & value
Gold layer making up 1/30 of total weight (3.33%). Lower-end gold-filled standard, often on chain stock. Less durable than 1/20 standard.
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: 1/30 / 1/30 GF. The mark differs by country and era, but the metal content is identical.
What 1/30 tells you
Gold layer making up 1/30 of total weight (3.33%). Lower-end gold-filled standard, often on chain stock. Less durable than 1/20 standard.
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 1/30 or an equivalent such as 1/30 GF.
- 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
- FTC Jewelry Guide 16 CFR Part 23.5
* Frequently asked
FAQ
- Q. Is 1/30 the same as 1/30 GF?
- A. Yes. 1/30, 1/30 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 1/30 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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