By Rocco Clayfield, trading as GoldPaid; the business incorporated as GOLDPAID LTD (company 17382540) on 5 August 2026 · Published · updated
Found a stamp 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.
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.
Start with the hallmark
British gold has been hallmarked for over six hundred years. A UK assay hallmark has three compulsory marks: the sponsor (maker) mark, the standard mark showing fineness, and the assay office mark. The date letter is a fourth, optional mark. The most common fineness marks on gold are 375 (9 carat), 585 (14 carat), 750 (18 carat), 916 (22 carat) and 999 (24 carat). The standard mark is sometimes a crown over the carat number on older pieces. None of these home checks gives you a figure; a figure needs the weight and the tested carat together, and an XRF assay settles the carat properly.
A hallmark is not absolute proof. Some unhallmarked gold is genuine, particularly Indian, Middle Eastern and antique pieces. Some hallmarks are forged. But on a modern British piece a clear hallmark is the strongest single home indicator of authenticity.
Weight, density and feel
Gold is heavy. Real gold feels dense for its size in the hand. Gold-plated brass or pewter pieces feel light when you weigh them on a kitchen scale next to a known-gold piece of the same dimensions. Pure gold has a density of 19.32 grams per cubic centimetre. Tungsten, the metal counterfeiters use to fake heavy gold, has a density of 19.25, almost identical, which is why weight alone cannot clear a suspect bar.
Water displacement is the home version of a density test. Lower the item on a thread into a measuring jug, note the water-level change in millilitres, and weigh the dry item on a scale. Divide weight by displacement and you get density. Only fine gold reads close to 19.3 g/cm3. An 18ct ring reads around 15.5 and a 9ct ring around 11.3, so compare the reading against the density for the carat rather than against pure gold.
The magnet test
Gold is not magnetic. A strong neodymium magnet should not stick to a real gold ring. If a magnet pulls on the item, the item contains iron or a magnetic alloy and is not solid gold. The reverse is not always true: many fakes use non-magnetic base metals like brass, so a non-magnetic reading by itself does not prove gold. The magnet rules things out, not in.
The ceramic and vinegar tests, handle with care
The traditional ceramic streak test rubs the item on an unglazed ceramic plate. A gold streak says gold. A black streak says the item is not gold. The problem is that the test scratches the piece. We strongly recommend against the streak test on hallmarked jewellery, antique items or anything with sentimental value. The damage is permanent and can knock more off the offer than the test was worth.
The vinegar test pours household vinegar on the item. Real gold does not react. Plated or base-metal items may dull or discolour. The vinegar test sometimes damages surface finish on plated pieces and is messy. Again, we recommend against it on anything you might want to sell at full value.
The skin discolouration myth
A common belief holds that real gold leaves a green or black mark on your skin. The mark is real enough. The conclusion people draw from it is wrong. Pure 24 carat gold does not react with skin. Lower-carat gold (9 carat and 14 carat especially) contains copper, which can react with sweat to leave a faint mark on some people. The skin mark therefore tells you the item contains some copper alloy. It does not tell you whether the piece is gold or base metal.
Treat skin discolouration as neutral information, not as a verdict either way.
Wear points and where to look for plate
Examine the high-wear areas on the piece, the inside of a ring shank where it has rubbed against a finger, the outside curve of a bangle, the back of a watch where it has worn against the skin. On a plated piece the gold layer wears through first at these points, exposing the base metal underneath as a darker, duller patch. On a solid gold piece, the wear surface looks the same all the way through. For pieces you suspect are plated, gold plated vs solid gold sets out five checks, and the acid testing kit guide explains what a home kit can and cannot tell you.
A loupe (10x magnification) helps. Hand-held jewellers loupes are inexpensive and let you see the wear pattern clearly.
When to stop testing and post for XRF
XRF testing is non-destructive and quick. The analyser reads the surface alloy in seconds, and taken at more than one point, alongside the weight and the wear points, it settles what carat the metal is. Once you have looked at the hallmark, felt the weight, run a magnet over it and inspected the wear points, you have done as much as you usefully can at home. Anything further risks damage. After the test, the tested carat and weight set the offer, not the stamp or the look of the piece.
GoldPaid tests every item received, free, with a full written valuation. WhatsApp photos to 07944 014111 and we will tell you whether your item is worth posting. Your parcel travels on Royal Mail Special Delivery Guaranteed, tracked and signed for. Royal Mail cover may be available up to £2,500 depending on the postal method and cover level used. GoldPaid can confirm the appropriate postal option before you post. If the lot may be worth more than £2,500, tell us first and we can split it across more than one prepaid label at no charge. Final offers depend on inspection, item weight, purity, hallmarks, stones, non-gold components, condition and the live precious-metal market.