Is It Real Gold? Reading Hallmarks on Vintage Jewelry
14K, 585, GF, RGP, 925 — decode the tiny stamps on vintage jewelry and learn which ones mean solid precious metal.
By The Grail Hunt · September 5, 2026 · 2 min read
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The tiny stamps inside a ring or on a clasp tell you a lot about a piece of jewelry — if you know how to read them. Here's a quick guide to the most common marks on vintage pieces.
Solid gold marks
Gold purity is measured in karats out of 24, or as a three-digit number in parts per thousand:
| Karat | Fineness mark | Gold content |
|---|---|---|
| 10K | 417 | 41.7% |
| 14K | 585 | 58.5% |
| 18K | 750 | 75% |
| 22K | 916 | 91.6% |
A mark like 14K or 585 indicates solid gold of that purity.
Marks that mean not solid gold
These marks look official but indicate only a thin layer of gold:
- GF — Gold Filled: a layer of gold bonded to a base metal. Durable, but not solid.
- RGP — Rolled Gold Plate: similar to gold filled, with a thinner layer.
- GP / GEP / HGE — Gold Plated / Gold Electroplated / Heavy Gold Electroplate: a very thin layer.
- 1/20 12K GF — a gold-filled marking showing the proportion and karat of the gold layer.
Silver marks
- 925 or Sterling — 92.5% silver
- 800 — 80% silver, common on European pieces
- Vermeil — sterling silver plated with gold
Maker's marks and signed costume jewelry
Many vintage costume pieces are valuable because of who made them, not what they're made of. Signed names like Trifari, Miriam Haskell, Eisenberg, Weiss and Schiaparelli are highly collectible. Look for the signature on the back or on a small plaque near the clasp.
Trust, but verify
Stamps can be faked or misleading — a stamp can be added to a base-metal piece. Simple checks include:
- Magnet test. Gold and silver aren't magnetic. If a magnet grabs a "solid gold" piece, something's wrong (though a magnetic clasp spring can be normal).
- Wear. Plated pieces often show a different-colored base metal where the plating has worn away on high points.
- Professional testing. A jeweler can perform an acid or electronic test for certainty.
Grail Hunt tip: Ask the seller for a close-up photo of the hallmark. A blurry or missing hallmark photo on a listing priced as solid gold is a reason to ask questions.
The bottom line
Learn the difference between solid-gold marks and gold-filled or plated marks, recognize the collectible costume jewelry signatures, and back up hallmarks with simple tests. It's the easiest way to separate treasure from trinkets.
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