Is 999.9 the same as FOUR NINES?

Yes. 999.9, FOUR NINES all denote the same material — 100.0% gold. Different markets and eras stamp it differently, but the purity is identical.

How much is 999.9 worth?

Its melt value is the gold spot price × 1.000 × 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 999.9 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 999.9 hallmark: meaning, purity & value

99.99% gold ('four nines'). LBMA Good Delivery and Royal Canadian Mint bullion standard. Higher purity than the 999.5/999 minimum.

Published May 30, 2026

Quick facts

Metal: Gold
Purity: 100.0%
Fineness: 999/1000
Karat: 24K
Common regions: international
Standard: LBMA

Stamps that mean the same thing

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

What 999.9 tells you

99.99% gold ('four nines'). LBMA Good Delivery and Royal Canadian Mint bullion standard. Higher purity than the 999.5/999 minimum.

How to value it

The melt value of a 999.9 piece is gold spot price × 1.000 × 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 999.9 or an equivalent such as FOUR NINES.
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

LBMA Good Delivery Rules
Royal Canadian Mint specifications
Wikidata Q897

* Frequently asked

FAQ

Q. Is 999.9 the same as FOUR NINES?: A. Yes. 999.9, FOUR NINES all denote the same material — 100.0% gold. Different markets and eras stamp it differently, but the purity is identical.
Q. How much is 999.9 worth?: A. Its melt value is the gold spot price × 1.000 × 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 999.9 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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