Fake gold is best caught by combining several checks rather than trusting a single test. At home you can check weight, dimensions, markings and whether the item reacts to a magnet, but only a professional with equipment such as an XRF analyzer, ultrasound or a fire assay can confirm that gold is genuine all the way through.
What fakes look like today
Knowing what you are up against is half the job. The most common types are:
- Gold-plated copies of coins – American Eagles, Buffalos, Krugerrands and pre-1933 US gold coins struck in brass or copper with a thin gold layer. They are often slightly off in weight or size.
- Tungsten-filled bars – tungsten is almost exactly as dense as gold, so the weight looks right. The bar is wrapped in real gold, which also fools surface tests.
- Jewelry with false stamps – a “14K” stamp on plated silver or base metal.
- Fake packaging and assay cards – copies of well-known refiners’ cards holding a counterfeit bar.
Checks you can do at home
None of these proves an item is genuine. They can only show that something is wrong.
1. Weight and dimensions
This is the most useful home check. You need a digital scale accurate to 0.01 g and a pair of calipers. Compare your readings with the official specification:
| Coin | Weight | Diameter | Fineness |
|---|---|---|---|
| American Gold Eagle 1 oz | 33.931 g | 32.70 mm | .9167 (22K) |
| American Gold Buffalo 1 oz | 31.1 g | 32.70 mm | .9999 (24K) |
| Krugerrand 1 oz | 33.93 g | 32.77 mm | .9167 (22K) |
A one-ounce coin that is several tenths of a gram off is a serious warning sign. Circulated pre-1933 coins may be slightly worn, but genuine coins lose remarkably little weight.
2. Magnet
Gold is not magnetic. If an item jumps to a strong neodymium magnet, it contains iron, nickel or cobalt. If it does not, that proves nothing: copper, brass and tungsten are not magnetic either.
3. Sound
A genuine gold coin gently tapped against another coin gives a long, clear ring, while plated base-metal copies tend to sound dull. You need a known genuine coin for comparison, so treat this as a hint only.
4. A close look
Use a 10x loupe on the design, lettering and edge. Fakes often have soft detail, uneven lettering or a poorly finished reeded edge. The American Gold Eagle was redesigned in 2021 with added anti-counterfeiting features, so compare a coin against official images for its year. On jewelry, look where it rubs: a different color showing through means plating.
Bars deserve extra care because a single piece can be worth thousands of dollars. Check that the refiner’s name, weight, fineness and serial number are stamped cleanly and match the assay card or invoice. Shallow, blurred stamping or edges that look like a seam between layers are reasons to have a bar tested.
What not to do at home
Avoid scratching, filing, drilling or using acid kits on coins and bars. They reduce value and only test the surface. The water displacement (density) test will not catch tungsten either, because tungsten (19.25 g/cm³) is almost as dense as gold (19.32 g/cm³).
How a professional tests gold
Dealers, jewelers and pawn shops use equipment that gives a more reliable answer:
- XRF analyzer – reads the metal composition in seconds without damaging the item. It only measures the surface, so it cannot see a tungsten core under a thick gold shell.
- Ultrasound – sound travels at different speeds through gold and tungsten, so a hidden core shows up.
- Electrical conductivity testers – check the metal beneath the surface of coins and bars.
- Fire assay – the most accurate method, but it destroys a small sample. It is mainly used for scrap and refining.
If in doubt, ask a dealer to test the item in front of you. Many established US dealers test as standard when buying back.
Special points for jewelry
Jewelry fakes are usually plated items or pieces of lower purity than claimed:
- Quality mark and trademark – a genuine “14K” or “585” mark should come with the maker’s registered trademark. A lone karat stamp is a reason to test.
- GP, GF, RGP or HGE – plated or gold-filled, containing little gold.
- 925 or vermeil on a yellow item – gold-coated sterling silver.
- Weight against size – gold is very heavy. A chunky chain that feels light may be hollow or another metal.
A jeweler can test purity with acid on a touchstone using a tiny, discreet sample. Leave this to a professional: the acids are hazardous.
Reducing the risk when you buy
- Buy from established dealers with a physical address and track record. You can compare them on our US bullion dealers page.
- Prefer bars from refiners on the LBMA Good Delivery list and coins from national mints such as the U.S. Mint.
- Keep invoices and certificates, and check that the serial number on a bar matches its card.
- Be wary of prices clearly below the market. Compare with live US gold prices.
- Pay by a traceable method rather than cash.
The highest risk comes from private sellers online, at shows and in classified ads. If you think you have been sold counterfeit gold, keep everything, get an independent test and report it to the FTC at ReportFraud.ftc.gov and to your state attorney general; for online sales, the platform should be told too.
Bottom line
Home checks (weight, dimensions, magnet, loupe) catch crude fakes but not well-made tungsten-filled bars. Reliable confirmation comes from professional testing with XRF, ultrasound or assay. Buying from established dealers and keeping paperwork lowers the risk.
Sources: LBMA – Good Delivery List (gold) · U.S. Mint · FTC – ReportFraud
This is general information, not tax or investment advice.
Frequently asked questions
Is real gold magnetic?
No. If an item sticks to a magnet it contains another metal, but passing the magnet test does not prove it is gold, because copper and tungsten are not magnetic either.
Can a density test detect fake gold?
It catches crude fakes but not tungsten-filled bars, because tungsten is almost exactly as dense as gold.
How much does a 1 oz American Gold Eagle weigh?
A 1 oz Gold Eagle weighs 33.931 g and measures 32.70 mm across. It contains one troy ounce of pure gold; the rest is alloy.
Where can I get gold tested in the US?
Established bullion dealers, jewelers and some coin shops offer testing, often with XRF or conductivity testers. Many test items as standard when buying them back.
