How to Check Gold Purity at Home: 7 Safe Tests

Gold is not magnetic. Hold a strong magnet (a neodymium magnet works best) near the piece: if it sticks or is pulled, the piece contains iron or nickel and is not solid gold. This test catches iron-based fakes quickly and safely, and it cannot damage the piece.

But it proves little on its own: many non-magnetic metals (copper, brass, lead, tungsten) are also non-magnetic, and a gold-plated piece will pass the magnet test. Use it as a first filter, not a verdict.

Gold is very dense (19.3 g/cm³) — one of the densest common metals. Drop the piece in water: real gold sinks quickly. A piece that floats or sinks slowly is not gold. A more precise version is the density test: weigh the piece, then weigh the water it displaces, and calculate the density — but this needs an accurate scale and care, and it is unreliable for hollow jewellery or pieces with stones.

The water test is safe and simple, but it only catches crude fakes. Tungsten, famously, has almost the same density as gold and passes density tests — which is why professional assay exists.

The skin test: rub the piece on your skin for a few minutes. Real gold does not leave a mark; some fake gold leaves a green or black stain (from copper in the alloy). But this test is unreliable — skin chemistry varies, and some real gold alloys can mark skin too. Treat it as a hint, not evidence.

The ceramic test: drag the piece across an unglazed ceramic tile. Real gold leaves a gold streak; fake gold leaves a black or grey streak. This test scratches the piece slightly, so use an inconspicuous spot — and do not use it on a piece you plan to sell in perfect condition.

The acid test is the most reliable home test. Gold testing acid kits (sold online and in jewellers' supply shops) contain acids of different strengths for different karats. Scratch the piece on a testing stone, apply a drop of acid to the streak, and watch: if the streak dissolves, the gold is below the karat the acid tests for; if it stays, the gold is at least that karat.

Acid testing needs care — the acids are corrosive, so wear gloves and work in a ventilated area — and it leaves a small scratch. It tests the surface, not the core, so a thickly plated fake can pass. For a definitive result, an electronic tester or an XRF assay is better.

Home tests catch crude fakes. They cannot catch sophisticated ones — tungsten-filled bars, thick plating, or gold alloyed just below the claimed karat. For any significant purchase or sale, a professional assay is cheap insurance: an XRF (X-ray fluorescence) test is non-destructive, takes minutes, and tells you the exact composition.

In India, BIS-recognised assay centres will test and hallmark gold for a small fee. In other countries, jewellers and bullion dealers offer XRF testing. If a seller refuses to let you test the gold independently, that refusal is your answer.