What "999.9 Fine Gold" Really Means for 10 oz Bars

Key Takeaways

•"999.9 fine" or ".9999" means 99.99% gold by mass; the remaining 0.01% is typically other metals allowed under refining standards.

•LBMA Good Delivery and refiner standards define purity and dimensions for large bars; retail 10 oz bars follow similar purity from accredited refiners.

•Refinery marks, serial numbers, and assay certificates document purity and origin; they support authenticity and resale.

•Purity is one factor in value; weight, refiner recognition, and documentation also matter for liquidity and pricing.

•Understanding purity helps you compare products and buy with confidence from reputable sources.

What Does 999.9 Fine Mean?

When a 10 oz gold bar is marked "999.9 fine" or ".9999," it means the bar is 99.99% gold by mass. The remaining 0.01% is usually a tiny amount of other metals (e.g., silver, copper) that may remain after refining or be added for hardness. This level of purity is the standard for investment-grade gold bars from major refiners and is sometimes called "four nines" fine.

The London Bullion Market Association (LBMA) sets standards for the wholesale market. Its Good Delivery list specifies minimum fineness for large bars (e.g., 995.0 minimum for gold). Many refiners produce bars well above that minimum; 999.9 is common for retail 10 oz bars from LBMA-accredited refiners. The U.S. Mint, Royal Mint, and other mints also publish purity standards for their products.

Why Purity Matters

Purity affects the gold content per bar. A 10 oz bar that is 999.9 fine contains 10 troy ounces of pure gold (with a negligible amount of other metal). If a bar were 99.5% fine, it would contain slightly less pure gold per unit of weight. For investment bars, 999.9 is the norm and supports consistent pricing and liquidity.

Refinery Marks and Documentation

Refiners stamp or engrave their name or logo, weight, and purity on the bar. Serial numbers link the bar to an assay certificate or card that states weight, purity, and refiner. These marks and documents are part of the chain of authenticity. LBMA-accredited refiners follow strict quality controls; their marks are recognized globally.

When you buy a 10 oz bar, you should receive an assay certificate (or equivalent) that matches the bar's serial number and states 999.9 (or 99.99%) fine gold. Retain this documentation for resale and insurance.

LBMA Good Delivery Context

The LBMA Good Delivery list applies to large bars (e.g., 400 oz or 12.4 kg for gold) used in wholesale clearing. Retail 10 oz bars are not Good Delivery size, but refiners on the Good Delivery list often produce 10 oz bars to the same purity and quality standards. Buying from an LBMA-accredited refiner (or a recognized government mint) gives you assurance that the bar meets institutional-grade purity and production standards. The World Gold Council publishes guidance on gold refining and purity. For more on gold investing and purity context, see an investing in gold resource.

Practical Implications

For buyers, 999.9 fine means you are getting investment-grade gold in a standardized form. Combined with refiner recognition and full documentation, purity supports liquidity and fair pricing when you sell. No bar is "better" gold than another by purity alone if both are 999.9; differences in premium and liquidity come from refiner, size, and market conditions.

Sources

London Bullion Market Association (LBMA), Good Delivery specifications, refiners list, and purity standards.

World Gold Council, gold refining and purity standards.

Major refiners (PAMP Suisse, Valcambi, Perth Mint, Royal Canadian Mint), product specifications.

U.S. Mint, Royal Mint, purity and specification guidance for minted products.

Questions & Answers

Common questions about 10 oz gold bars answered by our editorial team.

What does 999.9 fine mean?

999.9 fine (or .9999) means the bar is 99.99% gold by mass. The remaining 0.01% is typically trace other metals. This is the standard for investment-grade 10 oz bars from major refiners.

How does LBMA Good Delivery relate to 10 oz bars?

Good Delivery applies to large wholesale bars. Refiners on the LBMA list often produce 10 oz bars to the same purity and quality standards. Buying from an LBMA-accredited refiner gives assurance of institutional-grade purity and production.

Do I need the assay certificate?

Yes. The assay certificate documents weight, purity, and refiner and usually matches the bar by serial number. It supports authenticity, resale value, and insurance. Keep it and store a copy off-site.