Start with the stamp
Look inside the ring shank, on the clasp or on the back of a pendant for a karat or fineness mark:
| Mark | Gold content | Meaning |
|---|---|---|
| 24K, 999 | 99.9% | Pure gold |
| 22K, 916 | 91.67% | 22 karat |
| 18K, 750 | 75.00% | 18 karat |
| 14K, 585 | 58.33% | 14 karat |
| 10K, 417 | 41.67% | 10 karat, legal minimum for gold in the US |
Marks such as GP, GF, HGE, RGP or 1/20 14K GF mean plated or filled, not solid, and have almost no scrap value. 925 means sterling silver. A stamp is a claim, not proof, so test anything of real size.
Simple home checks
- Magnet. Gold is not magnetic. If a strong magnet sticks, the piece is not solid gold. If it does not stick, that proves nothing, because many fake metals are not magnetic either.
- Ceramic streak. Drag the piece across an unglazed ceramic tile. Gold leaves a gold streak. A black streak means something else. This can mark the item, so test an inconspicuous spot.
- Look for wear. Plating wears at edges and high points, showing a different metal underneath.
- Weight. Gold is dense. A piece that feels light for its size is suspect.
Density test
Weigh the piece in air, then suspended in water, and divide the weight in air by the loss in weight underwater. Pure gold is about 19.3 times the density of water. 14K is about 12.9 to 14.6 depending on the alloy, and 10K is lower. It needs a scale accurate to 0.01 g and only works on solid pieces with no stones.
Acid testing
Jeweler’s acid kits scratch a small mark on a testing stone and apply acids of different strengths to see which karat the mark survives. They work, but the acids are hazardous, can damage the item and need gloves, ventilation and eye protection. If you are not trained, have a jeweler do it.
Professional testing
An XRF analyser reads the alloy without damaging the piece and is used by many jewelers, coin shops and refiners. A fire assay is the definitive test for large lots. For high-value pieces, use these rather than home tests.
Once you know what it is
Work out the melt value with the scrap gold calculator, then read how to sell scrap gold.
Frequently asked questions
How can I tell if gold is real at home?
Check for a karat or fineness stamp, then use simple tests such as a magnet and an unglazed ceramic streak. These can rule out fakes but cannot prove purity. For anything valuable, use a jeweler's acid test or XRF.
Is gold magnetic?
No, gold is not magnetic. If a strong magnet sticks to a piece, it is not solid gold, but a piece that is not magnetic is not necessarily gold.
What does 585 mean on jewelry?
585 is the fineness stamp for 14K gold: 585 parts gold per thousand, or 58.33%.
What does GF or GP mean?
GF means gold filled and GP means gold plated. Both are a layer of gold over base metal and have almost no scrap value.
Does the acid test damage gold?
It leaves a small mark on a testing stone, but acid applied to the item itself can mark it. Use the stone method and have a professional do it if unsure.