Published 2 June 2026
The number explained
999 parts per thousand of pure gold is 99.9% pure by weight. The remaining 0.1% is trace metals from the refining process: silver, copper, sometimes platinum-group metals at the level of fractions of a percent. For most practical purposes, 999 is treated as pure gold.
Some refiners go further. 9999 (four nines, also written 999.9) is 99.99% pure gold and is the standard for the Canadian Maple Leaf, the Australian Kangaroo, and some Swiss refinery bars. The British Britannia coin moved to 9999 from 2013.
Why 999 is used for bullion
Bullion is gold held as a store of value, not as a wearable object. Investment-grade purity standardises the trade: a 1 oz bar of 999 gold from Umicore is interchangeable with a 1 oz bar of 999 gold from PAMP or Metalor for value purposes. Major refiners are LBMA-accredited (London Bullion Market Association), and their bars trade at a tight margin to spot.
A 999 coin or bar pays at very near the live spot price less a modest dealer margin, because the recovery cost is minimal. There is no refining work needed for a buyer to convert a 999 bar to liquid value.
Why 999 is not used in jewellery
Chinese 24k wedding bangles are sometimes sold at very near 999 purity and are kept as gift and savings pieces rather than worn daily. They show dents and softening of edges quickly.
How 999 sells at scrap
Investment-grade 999 bars and recognised bullion coins pay very close to the live spot price. The recovery cost is essentially zero (the metal is already at investment purity), so the margin is the smallest of any gold category. The price is set by the live precious-metal market at the moment of sale.
Final offers depend on inspection, item weight, purity, hallmarks, stones, non-gold components, condition and the live precious-metal market.
Identifying 999
- On bars: look for the refiner name (Umicore, PAMP, Valcambi, Metalor, Heraeus, Argor-Heraeus, Perth Mint), the weight (1g, 5g, 10g, 1 oz, 100g, 1 kg), the purity (999 or 9999), and the serial number.
- On coins: identify the design and the mint. Britannia, Maple Leaf, Krugerrand (post-2017), Australian Kangaroo, Vienna Philharmonic are all 999 or 9999.
- On jewellery: 999 stamps on rings or chains are rare. Where they appear, often Chinese imports, the alloy is genuinely close to pure and the piece is soft to the touch.
- When marks are unclear, post it. XRF confirms the alloy to within fractions of a percent.
- Original packaging, assay certificates and tamper-evident cards add to the resale value of bars and coins and should be sent with the parcel.
A note on counterfeit bullion
Tungsten-cored fake gold bars exist. Tungsten has a density very close to gold, so a fake can match the weight of a genuine bar. XRF measures surface composition, which detects most fakes immediately. Drilled or thinly plated counterfeits will read as gold on the surface and require ultrasound or specific gravity testing to identify. Investment-grade bars in tamper-evident packaging from LBMA-accredited refiners are the safest format.
Sending bullion by post
Royal Mail Special Delivery insures up to £2,500. Bars and coins above that value are typically sold by appointment to a specialist dealer rather than posted, because the insurance ceiling does not cover the contents. For sub-£2,500 parcels (which includes most one-off Britannia or Sovereign sales), the postal route works as it does for jewellery. The bullion is tested, weighed, and paid at close to the live market.
See how to sell gold by post for the full method.
A close
999 is the closest gold gets to a commodity. The pricing is transparent, the margin is small, and the test is fast. If you are sitting on bullion you do not want to keep, the route is straightforward and the figure is honest. For high-value bars and full coin collections, choose the specialist appointment route over the post so the cover matches the contents. For one or two coins, the postal route is the simpler answer.
Common questions
Is 999 gold pure?
Effectively yes. 99.9% by weight is gold. The remaining 0.1% is trace metals. For all practical valuation purposes 999 is pure.
What is 9999 gold?
99.99% pure gold, also called four-nines gold. Used by some refiners and mints for investment-grade products.
Are Britannia coins 999 gold?
Britannia coins minted before 2013 are 916. From 2013 onwards Britannias are 9999.
Does 24ct gold tarnish?
No. Pure gold does not tarnish or oxidise. Bars and coins kept properly look the same in 50 years as the day they were minted.
Can fake gold bars be detected by post?
XRF detects most counterfeits. Tungsten-cored fakes with full gold plating require additional testing such as ultrasound or specific gravity.
Should I sell sovereigns or Britannias?
Common-date Britannias and sovereigns pay close to spot bullion. Rare dates and proofs may carry numismatic premiums that exceed the bullion value.
Is there a hallmark on 999 bars?
Bars carry the refiner stamp, the weight, the purity and a serial number. They are not assay-office hallmarked because they are bullion, not jewellery.
What is the insurance ceiling for posting bullion?
Royal Mail Special Delivery insures up to £2,500. Higher-value bullion should be sold by appointment with specific transit cover, not by post.