How to Spot Fake Gold and Silver Bullion

Twenty years ago most fake bullion was crude and easy to spot. Today, tungsten-cored bars and well-struck counterfeit coins circulate widely enough that every buyer should know the basics. The good news is that gold and silver have unusual physical properties that are extremely hard to fake simultaneously, so a short sequence of cheap tests catches the overwhelming majority of fakes.

Start with dimensions and weight

Every genuine bullion coin has published specifications: diameter, thickness and gross weight, all tightly controlled. Gold is exceptionally dense at 19.32 grams per cubic centimetre, and silver at 10.49. No cheap substitute matches both the density and the dimensions of the real thing.

A digital scale accurate to 0.01 grams and a set of digital callipers cost very little and will catch most counterfeits on their own. A fake that has the right weight will almost always be too thick or too wide, because the substitute metal is less dense. A fake with correct dimensions will be too light.

• 1 oz Gold Krugerrand: 32.77 mm diameter, 2.84 mm thick, 33.93 g
• 1 oz Gold Maple Leaf: 30.00 mm, 2.87 mm, 31.10 g
• 1 oz American Silver Eagle: 40.60 mm, 2.98 mm, 31.10 g
• 1 oz Britannia (silver): 38.61 mm, 3.00 mm, 31.10 g

The magnet slide test

Gold and silver are not magnetic, so a genuine coin will not stick to a magnet. That much is obvious and easy to defeat, since lead, tungsten and copper are not magnetic either. The more useful version is the slide test, which exploits a different property.

Silver is the most electrically conductive element known. Slide a strong neodymium magnet down a tilted silver bar and eddy currents cause it to descend visibly slowly, as if through treacle. Most fakes do not reproduce this. Gold shows a weaker but still detectable effect. The test is not conclusive on its own, but a fake that passes the slide test is a rare thing.

The ping test

Balance a coin on a fingertip and tap it gently with another coin. Genuine silver rings with a long, high, sustained tone, often for several seconds. Genuine gold produces a shorter, softer ring. Base metals and plated fakes produce a dull thud that dies almost immediately.

Free smartphone apps can analyse the frequency and compare it against a known reference for that coin type. It is a surprisingly reliable test for silver in particular, though it does not work on coins sealed in plastic capsules or assay cards.

What catches the sophisticated fakes

Tungsten has almost exactly the same density as gold, which is why tungsten-cored gold bars are the premium counterfeiter’s tool of choice. Weight and dimensions will both pass. What defeats them is ultrasonic thickness testing, which measures the speed of sound through the metal and reveals the internal boundary between the gold skin and the tungsten core. Sound travels roughly twice as fast through tungsten as through gold.

Specific gravity testing, which weighs an item in air and then in water, is cheap and catches almost everything except tungsten. XRF analysers give an instant surface composition reading but cannot see through a plated exterior, so they are best combined with another method. Larger bars are more attractive to counterfeiters than coins, precisely because there is more room for a core.

The best defence is where you buy

Almost all documented counterfeits enter the market through private sales, auction sites and marketplace listings rather than through established dealers. A dealer with a physical premises, a long trading history and membership of a recognised trade body has vastly more to lose from selling a fake than any profit it could produce.

Buy sealed bars in their original assay packaging where possible, keep the certificate, and be sceptical of anything priced meaningfully below the going rate. A one ounce gold coin offered five per cent under spot is not a bargain; it is a warning.

Keep a record you can actually use

Documentation is your best long-term protection. Record the dealer, the date, the price paid, the serial number of any bar and photographs of both faces. If a question is ever raised about a piece, that record is what resolves it. BullionTally stores purchase details and notes for every item in your portfolio on your own device, so you have a complete provenance trail without publishing your holdings to anyone.

You can also find reputable dealers near you using our dealer finder, which searches local coin and bullion dealers by location.