How to Tell if Gold Is Real: 8 Tests from Home to the Lab
Why no single test is enough
Fake and misrepresented gold ranges from cheap plated jewelry sold as solid gold to sophisticated counterfeit bars with a tungsten core. Each test checks one property — magnetism, colour, density, chemical reaction or composition — and each can be fooled. Combining two or three simple tests catches most fakes; anything valuable deserves a professional check. The tests are listed from the gentlest to the most reliable.
1. Read the hallmark
Use a magnifying glass to find the stamp, usually inside a ring band, on a clasp or near a chain’s end. Genuine marks show a karat (10K, 14K, 18K, 22K) or fineness (417, 585, 750, 916, 999), often with a maker’s mark and, in many countries, an assay-office or standards mark. Our guide to karats explains every number.
Some stamps tell you the item is not solid gold: GP or GEP (gold-plated), HGE or HGP (heavy gold electroplate), GF or a fraction such as 1/20 12K (gold-filled), RGP (rolled gold plate) and 925 on a yellow item (gold-plated sterling silver, or vermeil). Remember that a stamp is only a claim — counterfeiters can stamp anything — so treat it as a starting point.
2. Look closely at wear and colour
Plated items often show a different colour where the plating has worn through: on edges, clasps and the underside of rings. Green or black marks on your skin suggest a base metal underneath. Real gold does not rust or tarnish much, although low-karat alloys can darken slightly over time.
3. The magnet test
Gold is not magnetic. If a strong magnet (a neodymium magnet works best) pulls the piece firmly, it is not solid gold or contains a steel core. The test only rules things out: copper, brass, lead and tungsten are also non-magnetic. Note that clasps may contain a small steel spring.
4. The ceramic streak test
Gently drag the item across the unglazed underside of a ceramic tile or plate. Real gold leaves a gold-coloured streak; a black or grey streak suggests another metal. This test can scratch the piece, so avoid it on anything delicate or valuable, and it does not detect thick plating.
5. The density (water) test
Pure gold is extremely dense: 19.32 grams per cubic centimetre, far more than silver (10.5), copper (9.0) or brass (about 8.5). You can measure density with a precise scale and a cup of water:
- Weigh the item dry and note the result (A).
- Put a cup of water on the scale and reset it to zero.
- Hang the item on a thin thread so it is fully under water without touching the sides or bottom. The scale now shows the weight of water it displaces (B).
- Density = A ÷ B.
Typical results: 24K about 19.3, 22K about 17.7–17.9, 18K about 15.2–15.9, 14K about 12.9–14.6 and 10K about 11.4–12.4 (white and rose alloys sit at the edges of these ranges). The test is excellent for coins and bars but less precise for small or hollow items. Its big weakness is tungsten, whose density of 19.25 is almost identical to gold’s — which is why counterfeiters use tungsten cores in fake bars.
6. The acid test
Jewelers rub the item on a black touchstone and apply nitric acid solutions calibrated for different karats. The streak dissolves if the gold is below the tested purity. It is quick, cheap and accurate for karat, but it only tests the surface where it is applied, and acids are hazardous — leave it to professionals or follow kit instructions carefully.
7. Electronic testers
Electronic gold testers measure how the metal conducts electricity or reacts electrochemically and display a karat estimate. They are fast and non-destructive. Specialised bullion verifiers measure resistivity through the whole thickness of a coin or bar and can detect tungsten cores that a surface test would miss.
8. X-ray fluorescence (XRF) and fire assay
An XRF analyser fires X-rays at the surface and reads the exact mix of metals in seconds without damage. Many buyers and refiners use one. XRF reads only the outer layer, so thick plating can mislead it. The definitive method is fire assay, used by refiners, which melts a sample and measures the gold content precisely — but it destroys the sample.
Checking gold coins and bars
- Compare weight, diameter and thickness with the mint’s official specifications; fakes are often slightly off.
- Many genuine coins "ring" with a long, clear tone when gently tapped; fakes tend to sound dull.
- Look for crisp details, correct fonts and security features on modern coins and bars.
- Prefer sealed products with assay cards and buy from reputable dealers. A price far below spot is the biggest warning sign of all.
Once you know your gold is genuine, find its value with our gold calculator or read how to sell gold for the best price.