How to Check Gold Purity Before Buying
How to check gold purity before buying: hallmarks, magnet and acid tests, electronic testers, when to request an assay, and your consumer rights.
Knowing how to check gold purity before buying protects you from the most expensive mistake in the gold market: paying 22k prices for 18k gold. Every legitimate piece carries clues, from hallmark stamps to the invoice. Here is how to read them, plus the quick tests you can do yourself.
How to Check Gold Purity: Reading Hallmarks
Look for the fineness stamp: 999 means 24k, 916 means 22k, 875 means 21k, 750 means 18k, and 585 means 14k. In Dubai, genuine pieces also carry the Dubai Central Labs or assay office mark. No stamp, or a blurry one, is a reason to pause. Compare karat values on our per-gram reference.
Quick Tests You Can Do Yourself
A magnet test rules out the crudest fakes: gold is not magnetic, though clasps may contain steel springs, so test the main body. The acid test is more decisive: a jeweler scratches the piece on a stone and applies acid for the claimed karat. Neither test is perfect, which is why the invoice matters most. See how karats compare in our 14k vs 18k guide.
Electronic Testers and XRF Scanners
Reputable shops own electronic gold testers or X-ray fluorescence scanners that read metal content without damage. Ask the dealer to test the piece in front of you; refusal is a red flag. These machines verify the alloy matches the stamped karat within seconds. The same XRF verification is standard when you buy gold bars in Dubai.
The Invoice Is Your Strongest Protection
Insist on an invoice showing weight in grams, karat, per-gram rate, and making charges separately. In the UAE and Saudi Arabia, consumer protection laws back you if the piece later tests below the invoiced karat. Buy from established shops using our Dubai buying guide, and sanity-check prices against the live UAE rate.
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Certified Financial Planner and Precious Metals Valuation Specialist with over a decade of experience analyzing GCC physical bullion markets and jewelry economics.
View Full Analyst Profile & Disclosures ➔Frequently Asked Questions
What do the numbers 916 and 750 mean on gold?
They are fineness marks showing pure gold content per thousand parts. 916 means 22 karat (91.6 percent pure), 750 means 18 karat, 875 means 21 karat, 585 means 14 karat, and 999 means 24 karat. Match the stamp to the karat on your invoice.
Does the magnet test really work on gold?
Only as a rough screen. Real gold is not magnetic, so a piece that sticks strongly to a magnet is fake. But non-magnetic fakes exist too, and steel springs in clasps can easily confuse the test, so never rely on it alone.
Can I test gold purity at home?
You can do basic checks: inspect the hallmark with a loupe, try the magnet test, and check that the weight feels right for the size. For certainty, use an acid test kit from a jeweler supplier or ask a shop to run an electronic test in front of you.
What is the most accurate gold purity test?
Fire assay is the gold standard but destroys a sample. For buyers, X-ray fluorescence scanning is the best non-destructive option, and most reputable Dubai dealers will run it free before a sale. Dubai Central Labs also offers official assaying services.
What if my gold tests below the invoiced karat?
Keep the invoice and get a written assay report, then return to the seller. Consumer protection laws in the UAE and Saudi Arabia cover misrepresented karat, and regulators take hallmark fraud seriously. This is why an itemized invoice matters more than any verbal promise.