* Gold hallmark
The 833 hallmark: meaning, purity & value
20-karat gold fineness. Uncommon outside Japan and Finland; historically used in select European pieces.
Published May 30, 2026
Quick facts
- Metal
- Gold
- Purity
- 83.3%
- Fineness
- 833/1000
- Karat
- 20K
- Common regions
- Japan, FI, international
- Density
- 16.5 g/cm³
- Melting point
- 1010 °C
- Standard
- ISO 9202
Stamps that mean the same thing
This purity may be struck into jewelry as any of: 833 / 20K / K20. The mark differs by country and era, but the metal content is identical.
What 833 tells you
20-karat gold fineness. Uncommon outside Japan and Finland; historically used in select European pieces.
How to value it
The melt value of a 833 piece is gold spot price × 0.833 × 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 833 or an equivalent such as 20K.
- Weigh the piece and estimate its volume — the density should land near 16.5 g/cm³ for this alloy.
- 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.
* Frequently asked
FAQ
- Q. Is 833 the same as 20K?
- A. Yes. 833, 20K, K20 all denote the same material — 83.3% gold. Different markets and eras stamp it differently, but the purity is identical.
- Q. How much is 833 worth?
- A. Its melt value is the gold spot price × 0.833 × 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 833 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 (16.5 g/cm³ for this alloy), 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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