How to identify fake gold: UK guide

Why fake gold exists

Most "fake" gold on the second-hand market is not a scam item. It is plated, filled, rolled or stamped jewellery that was always sold as such but has drifted from its paperwork over decades. The usual suspects are a rolled-gold watch from the 1960s or 70s, a chain bought abroad and remembered as better than it was, and costume pieces that ended up in the same inherited jewellery box as the real thing. An at-home check is there to flag those items before anyone mistakes them for solid gold. On arrival, XRF readings taken at several points, including wear edges and joints where a base core shows through, are what separate plate and fill from solid gold.

Test 1: The magnet test

Pure gold is not magnetic. If a piece is attracted to a strong neodymium magnet, it contains a magnetic base metal (typically iron, nickel or steel) and is not solid gold. The reverse is not proof: many plated, filled or low-carat alloys are also non-magnetic. One caveat before you condemn a chain: the spring inside a genuine gold clasp is usually steel, so the clasp will often snap to a magnet even when every link is solid gold. Test the links, not the fastening. A magnet is a fast fail-test, not a pass-test.

Test 2: Density (the bench-jeweller’s test)

Gold is very dense. Pure 24ct weighs about 19.3 g/cm³. 18ct weighs about 15.5 g/cm³, 9ct about 11.3 g/cm³. If you can measure the item’s weight and the volume of water it displaces, the density tells you a lot. A worked illustration: a plain band weighing 6.20 g that displaces 0.40 ml of water has a density of 15.5 g/cm³, right where 18ct sits. If the same ring displaced 0.70 ml, the density would be 8.9 g/cm³, which is brass territory. You need scales that read to 0.01 g and a narrow measuring vessel to get anywhere near this at home. The catch is hollow items, stone settings and solder, all of which throw the figure off. A bench jeweller will isolate the metal first; at home, this is a rough sanity check, not a verdict.

Test 3: The ceramic plate scratch

A piece of real gold leaves a gold-coloured streak on an unglazed ceramic tile. A piece of brass or plated metal usually leaves a darker, blacker streak. This test does mark your item, so use the inside of a clasp or somewhere out of sight. It is also a rough check, not proof, and not advisable on anything sentimental.

Test 4: Read the hallmark properly

A UK hallmark is the easiest test most people miss. 375 = 9ct, 585 = 14ct, 750 = 18ct, 916 = 22ct, 999 = 24ct. A standing lion is a sterling-silver mark, not a gold mark, so a "lion" on a yellow piece usually means the yellow is gold-coloured plate over silver. Marks like GP, GF, RG, HGE and 1/20 identify plated, filled or rolled-gold items rather than solid gold. Check the wear points too: plating goes first where the piece rubs, the edges of a ring shank, the crowns of chain links, the back of a pendant. A different colour, grey, pink or brassy, showing through at those spots is plate wearing off a base metal.

Counterfeit marks exist but are rarer than people assume; a UK assay-office punch struck into the metal is hard to fake convincingly. See the gold hallmark guide for the symbol set.

Test 5: The acid test (and why we do not use it)

The traditional jeweller’s acid test scratches the metal onto a touchstone and applies an acid graded for a carat (e.g. 9ct, 18ct, 22ct). If the streak dissolves under a higher-carat acid, the item is below that carat. It is informative, and it permanently marks your piece. We replaced acid testing with XRF for this reason: XRF measures the same composition without leaving a trace, so if you decline our offer your items go back to you exactly as they came in.

When in doubt, ask before posting

If a clear photo of the mark, the back of the clasp and the inside of a ring is sent on WhatsApp, an experienced eye can usually tell whether a piece is worth posting in. There is no charge for that conversation and no obligation to send anything afterwards. If you do send it, the piece is checked by XRF rather than acid, so nothing is scratched.

Common questions