Hallmarks & Carats

What does 999 or 999.9 mean on gold? 24ct fine gold explained

999 on gold means 24 carat fine gold: 999 parts in every 1,000 are pure gold. 999.9, known as four nines and sometimes written 9999, is purer still at 99.99%, and it is also 24 carat. Both are standard for investment bars and most modern bullion coins, and both are too soft for jewellery that is worn every day.

By Rocco Clayfield, trading as GoldPaid; the business incorporated as GOLDPAID LTD (company 17382540) on 5 August 2026 · Published · updated

What does 999 mean on gold?999 is the parts-per-thousand mark for fine gold, meaning 999 parts of every 1000 by weight are pure gold. In carat terms this is 24 carat. Some refiners produce 999.9 (four nines) gold, which is even purer. 999 is the standard for investment-grade bars from major refiners (Umicore, PAMP, Valcambi, Metalor, Heraeus) and for most modern bullion coins (Britannia, Maple Leaf, Australian Kangaroo, Vienna Philharmonic; the Krugerrand and the American Gold Eagle are exceptions, struck in 22ct). It is rarely used in jewellery because the metal is too soft for everyday wear.

Found 999 on your piece? Send us a photo of it

Photograph the number stamped inside the ring or on the clasp, then the whole piece, and send both on WhatsApp. We will reply with what the mark means and a rough estimate of what we would pay. No obligation, and nothing needs posting.

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No WhatsApp? Call 07944 014111, 8am to 9pm.

Not sure what the mark says? Use the hallmark lookup. Final offers depend on inspection, item weight, purity, hallmarks, stones, non-gold components, condition and the live precious-metal market.

The number explained

999.9 gold is 24 carat. The stamp means 999.9 parts per thousand, or 99.99% pure gold by weight, sometimes written 9999 and known as four-nines gold. It is the standard purity for modern bullion bars and for coins such as the post-2013 Britannia.

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 per cent. 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 needs no refining, so it sits closer to the market than any other carat, and the offer reflects the fine gold we measure and the live market.

Why 999 is not used in jewellery

Pure gold is soft enough to be marked by a fingernail. A 999 ring would deform within months of wear. Jewellery uses alloyed gold (375, 585, 750, 916) to gain enough hardness to survive daily use.

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

GoldPaid values 24ct on the fine gold we measure and the live market. Specialist bullion dealers often pay closer to spot for recognised bars and coins in their original packaging, which is worth checking before you post bullion.

Final offers depend on inspection, item weight, purity, hallmarks, stones, non-gold components, condition and the live precious-metal market.

Identifying 999

  1. 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.
  2. On coins: identify the design and the mint. Britannia, Maple Leaf, Australian Kangaroo and Vienna Philharmonic are all 999 or 9999. The Krugerrand is not: it is struck in 22 carat (916) throughout, and still holds a full ounce of fine gold.
  3. 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.
  4. Anything you cannot place from the stamps can still be tested. XRF reads the alloy to within fractions of a per cent.
  5. 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, so it catches plated base metal quickly, but a tungsten core under a thick gold skin reads as gold on the surface and needs 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 cover may be available up to £2,500 depending on the postal method and cover level used. Several coins worth more than that together can be split across more than one prepaid label, but a single bar or one-ounce coin worth more than £2,500 cannot be split, so message us before you post and GoldPaid can confirm the appropriate postal option before you post. GoldPaid is postal-only and covers the whole of the UK. For parcels under £2,500, the postal route works as it does for jewellery: a bar is tested, weighed and valued against the live market, and for coins, send a photo on WhatsApp first and we will tell you how we would value them before you post anything. How fine gold is priced once it has been tested sets out the method.

See how to sell gold by post for the full method.

Post it, or take it to a bullion dealer

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, a bullion dealer you can visit in person may suit better than the post, because Royal Mail cover may be available only up to £2,500. For one or two coins, the postal route is the simpler answer.

Next step: have the mark checked against the metal

A hallmark records the standard a piece was assayed at. It does not tell you what the alloy measures now, what the piece weighs once stones and non-gold parts are set aside, or where the market sits today. Send a photo of the punches on WhatsApp and we will tell you what can reasonably be read from an image. Post the piece and it is XRF-tested on arrival, with a written offer showing the purity found, the weight and the figure for each piece. Decline it and the tracked return costs you nothing. Accept it and we aim to pay by Faster Payments within one working hour of your acceptance.

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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 and often written 999.9. Like 999, it is 24 carat. 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 trade on their gold content. 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 cover ceiling for posting bullion?

Royal Mail Special Delivery cover may be available up to £2,500 depending on the postal method and cover level used. If a lot is worth more than that, tell us before you post: several coins can be split across more than one prepaid label, a single bar cannot, and GoldPaid can confirm the appropriate postal option before you post.

Not the question you had? The full GoldPaid FAQ covers the rest, from postal cover and ID checks to what happens if you decline the offer.

Related guides

Reference pages

Photo first, written offer after testing

Get a written offer, then decide

Send a photo on WhatsApp and ask anything you like. We reply with an idea of what it is worth, and the free Royal Mail Special Delivery label only goes out when you ask for it.

Free prepaid label, usually sent within 30 minutes during working hours. Free tracked return if you decline. We aim to pay by Faster Payments within one working hour of acceptance.