Is it real gold? Five tests you can do yourself

1. The hallmark. Look for 333–999, «K» or «ct» with a magnifying glass. The hallmark is the quickest indicator, but it may have worn off — or be forged.

2. The magnet. Real gold is not magnetic. If a strong magnet pulls at the item, it is not real gold. No reaction, however, doesn't rule out fakes made from non-magnetic metals such as brass or tungsten.

3. Weight and size. Gold is heavy: the density is 19.3 g/ml for pure gold and 13–15 g/ml for 8–18 karat. If a large chain feels remarkably light, it's unlikely to be gold.

4. The water test (Archimedes). Weigh the item, measure the displaced water in a measuring glass, and divide. The table below shows the expected figures. The method requires a 0.1 g scale and a bit of care, but reveals most fakes — including tungsten, which resembles gold in colour.

5. The professional test. X-ray fluorescence (XRF) measures the alloy in seconds without damage, and the acid test checks the fineness on an invisible scratch. Both jewellers and most buyers test for free — use it as a final check before you sell.

Expected density per karat

Pure gold 19.3 · 22 karat 17.7–18.0 · 18 karat 15.2–15.9 · 14 karat 13.1–14.0 · 8–9 karat 11.5–12.7 g/ml. If your figure is well below the range, it's due to cavities, stones — or the item not being gold at all.

Signs of gold plating

A golden colour that chips off at the edges to reveal grey or reddish-brown metal underneath is the classic sign of gold-plated brass or silver. Genuine gold jewellery is gold all the way through — scratches are always golden-coloured.