You can rule out some fakes at home in a few minutes, but you cannot confirm real gold at home. The checks that are safe to do on your kitchen table can tell you a piece is probably not solid gold. They cannot tell you it is, and they cannot tell you the karat. That takes testing.
This guide covers what to look for first, which home checks are worth doing, which popular ones to skip, and what a jeweler actually uses to confirm gold.
Start with the stamp
Before any test, look for a mark. Check the clasp, the inside of a ring band, the back of a pendant and the small tag near a necklace clasp. A magnifier or your phone’s zoom makes this much easier.
These are the marks that matter.
- Karat marks such as 10K, 14K, 18K or 22K, or the fineness numbers 417, 585, 750 and 916, describe solid karat gold. The FTC Jewelry Guides also recognize 9K as a karat marking.
- Plating and filled marks such as GF, RGP, GEP, HGE or GP mean a layer of gold over another metal, even when a karat number appears with them. “14K GF” is gold filled, not 14K gold.
- A maker’s mark next to the karat stamp is a good sign. Federal law requires a maker or dealer who applies a quality mark like 14K to goods shipped across state lines to apply its trademark as well.
A stamp is a claim, not proof. Marks can be worn, misread or simply false, and plenty of real gold carries no mark at all. Use the stamp to decide what you are probably holding, then confirm it.
Home checks worth doing
These checks will not damage anything, and they can tell you quickly when a piece is clearly not solid gold.
The magnet check
Gold is not magnetic. Hold a strong magnet, such as a rare earth magnet from a hardware store, close to the piece. If the body of the piece is clearly pulled toward the magnet, it is not solid gold.
Passing the magnet check does not mean the piece is gold. Many metals used in fakes and in plated jewelry, such as brass and copper, are not magnetic either, and gold plated tungsten passes too. Treat a pass as “not ruled out,” nothing more.
The wear check
Gold plating and gold filled layers wear through first where a piece rubs. Look closely at the edges of chain links, the underside of a ring band and the corners of a clasp. A different color showing through, often silver gray or coppery, suggests a gold layer over another metal. Solid gold should look the same color at a worn edge as everywhere else.
The paperwork check
Receipts, appraisals and original boxes do not prove a piece is gold, but they tell a jeweler what to check for and can help identify a maker. Keep them with the piece.
Home tests to skip
Several tests circulate online that either damage the piece or give answers you cannot trust.
- Scratching on unglazed ceramic or a tile. This removes metal and leaves a mark on the piece, and on a plated item it only tests the plating.
- Home acid kits. Acid testing is a real method, but it works by comparing a streak of the metal against reference samples, and on a suspect piece it can mean cutting a small notch to reach fresh metal. Done at home without reference needles or practice, it risks damaging a piece and misreading the result. The acids are hazardous to handle.
- Biting, the float test, vinegar and the skin discoloration test. None of these measures gold content. A piece can pass or fail them for reasons that have nothing to do with gold.
- Weighing and measuring at home. Density testing sounds scientific, but research published by GIA found it the least suitable of the methods it compared for checking gold content, so it is not worth attempting at home.
If the magnet and wear checks leave you unsure, stop there. The next step is a test that does not depend on guesswork.
What a jeweler tests
Jewelers and gold buyers have a few tools, and they may use more than one on the same piece.
Touchstone and acid
This is the traditional method. The jeweler rubs the piece on a dark testing stone to leave a thin streak, rubs reference needles of known karat beside it, and applies acids of measured strength. Comparing which streaks dissolve and which remain shows the karat range. GIA’s instructions for the method call for taking the sample from a spot that is not visible and away from solder joints, because solder can give a false reading.
Electronic gold testers
Electronic testers estimate karat by passing a small electrical signal through the metal where the probe touches it. They are fast and do not use acid, but a reading taken at the surface may not see past a thick gold layer, so a doubtful result calls for a second method.
X ray fluorescence (XRF)
An XRF analyzer reads the metals in a piece without harming it. GIA researchers describe XRF as the only truly nondestructive method among the chemical analysis tools they compared, and note that it can measure the main metals in common gold alloys. It can also flag plating, often by picking up the base metal underneath or a nickel layer between the gold and the base.
What testing can and cannot tell you
Counter testing is designed to answer the questions most sellers have: is this gold, is it solid or a layer over something else, and roughly what karat is it. It is not the same as a refinery assay. A GIA study comparing several methods found that none of them reliably measured gold content within the three parts per thousand tolerance that federal marking rules allow, so exact purity is a job for a refinery assay, not a counter test.
If the piece turns out to be gold filled or plated
A piece can test as gold on the surface and still be a gold layer over base metal. If that is what you have, our guide on whether gold plated or gold filled jewelry is worth anything explains what those marks mean for value. If your question is about silver rather than gold, we have a separate guide on how to know if you have real silver.
Having gold tested at Clark Pawners & Jewelers
Bring the piece as it is, with any stamps, boxes or paperwork. We test for purity, weigh the piece and tell you what we find. If it is solid gold, our page on gold, silver and platinum buying in Lincoln Park explains how karat, weight and the day’s metal market set an offer.
Questions people ask about testing gold
Only partly. Gold is not magnetic, so a strong pull from a magnet means the piece is not solid gold. A piece that does not react could still be plated brass, copper or tungsten, so the magnet can rule gold out but cannot confirm it.
It is a good sign but not proof. Stamps can be worn, misread or false. A karat stamp with a maker’s trademark beside it is more reliable than a karat stamp alone, and testing confirms it.
Done properly on a testing stone, it uses a tiny streak of metal. On a suspect piece, a tester may file a small notch in a hidden spot to reach fresh metal under any plating. That is why it is best left to a jeweler.
Yes. Acid testing on fresh metal and XRF analysis can both show whether gold is solid or a layer over a different metal. XRF can often detect the base metal or a nickel layer beneath the plating without harming the piece.
These are fineness marks in parts per thousand. 585 means 58.5 percent gold, which corresponds to 14K, and 750 means 75 percent gold, which corresponds to 18K.
Have your gold tested in Lincoln Park
Bring your jewelry to our Lincoln Park store and we will test it and tell you what you have. An evaluation is information, not a commitment, and you are free to take everything home.
Clark Pawners & Jewelers
2626 N Clark Street
Chicago, IL 60614
773-528-7900
