Is 625 the same as 15ct?

Yes. 625, 15ct, 15K all denote the same material — 62.5% gold. Different markets and eras stamp it differently, but the purity is identical.

How much is 625 worth?

Its melt value is the gold spot price × 0.625 × the weight in grams. Buyers then deduct roughly 5–15% for refining and margin, so a quoted buy-back price sits a little below that theoretical figure.

How do I confirm a 625 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 hallmark

The 625 hallmark: meaning, purity & value

15-karat gold (62.5%). Legal in the UK only between 1854 and 1932; useful for dating antique British jewelry. Replaced by streamlined 9/14/18/22 karat options under 1932 reform.

Published May 30, 2026

Quick facts

Metal: Gold
Purity: 62.5%
Fineness: 625/1000
Karat: 15K
Common regions: UK-historic

Stamps that mean the same thing

This purity may be struck into jewelry as any of: 625 / 15ct / 15K. The mark differs by country and era, but the metal content is identical.

What 625 tells you

15-karat gold (62.5%). Legal in the UK only between 1854 and 1932; useful for dating antique British jewelry. Replaced by streamlined 9/14/18/22 karat options under 1932 reform.

How to value it

The melt value of a 625 piece is gold spot price × 0.625 × weight (g). A buyer typically deducts 5–15% for assay, refining, and margin, so the cash offer lands just under that figure. Stones and complex settings are usually excluded from the metal weight.

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 625 or an equivalent such as 15ct.
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

UK Hallmarking historical regulations 1854-1932

* Frequently asked

FAQ

Q. Is 625 the same as 15ct?: A. Yes. 625, 15ct, 15K all denote the same material — 62.5% gold. Different markets and eras stamp it differently, but the purity is identical.
Q. How much is 625 worth?: A. Its melt value is the gold spot price × 0.625 × the weight in grams. Buyers then deduct roughly 5–15% for refining and margin, so a quoted buy-back price sits a little below that theoretical figure.
Q. How do I confirm a 625 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

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