Is 999 the same as 999.9?

Yes. 999, 999.9, .999, PURE, K24, FINE GOLD all denote the same material — 99.9% gold. Different markets and eras stamp it differently, but the purity is identical.

How much is 999 worth?

Its melt value is the gold spot price × 0.999 × 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 999 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 (19.32 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.

* Gold hallmark

The 999 hallmark: meaning, purity & value

Fineness mark for pure 24-karat gold. Used internationally on bullion and pure-gold jewelry. Disambiguate by context: '999' on silver indicates fine silver, not gold.

Published May 30, 2026

Quick facts

Metal: Gold
Purity: 99.9%
Fineness: 999/1000
Karat: 24K
Common regions: international
Density: 19.32 g/cm³
Melting point: 1064 °C
Standard: ISO 9202

Stamps that mean the same thing

This purity may be struck into jewelry as any of: 999 / 999.9 / .999 / PURE / K24 / FINE GOLD. The mark differs by country and era, but the metal content is identical.

What 999 tells you

Fineness mark for pure 24-karat gold. Used internationally on bullion and pure-gold jewelry. Disambiguate by context: '999' on silver indicates fine silver, not gold.

How to value it

The melt value of a 999 piece is gold spot price × 0.999 × 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 999 or an equivalent such as 999.9.
Weigh the piece and estimate its volume — the density should land near 19.32 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.

Sources

ISO 9202:2019
Wikidata Q897

* Frequently asked

FAQ

Q. Is 999 the same as 999.9?: A. Yes. 999, 999.9, .999, PURE, K24, FINE GOLD all denote the same material — 99.9% gold. Different markets and eras stamp it differently, but the purity is identical.
Q. How much is 999 worth?: A. Its melt value is the gold spot price × 0.999 × 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 999 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 (19.32 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.

* Try it

Identify the jewelry in your hand, right now.

Just take a photo — AI reads the metal, gemstone, hallmark, era, and an estimated value range in seconds. First two scans free, no account required.

Download on the App Store

* Related