Identifying Fraudulent Bullion, Coins, and Thin Ingot Alloys

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The price of gold and other precious metals has skyrocketed in recent years, allowing scammers to capitalise on the surge by introducing counterfeit products into the market.

The precious metal is currently trading at $1,809.63/oz as of 09/07/2020, which is the highest level since 2013. However, as the demand keeps rising, so as the attempts of scammers to deceive traders and investors.

According to the CNBC article, a big jump in the price of gold means an increase in gold-related scams (Smith, 2020). Even with the industry’s strict quality standards, the counterfeit product market still regularly slips significant amounts of gold bars every year.

In the most recent news, 83 tonnes of gold valued at $2.92 billion were used to obtain loans from 14 financial institutions, but many of them have turned out to be gilded copper. (Durden, 2020)

What is a Fake Gold Bar?

A fake gold bar is a block of cheaper metal that is plated or covered with gold. Counterfeits have inclusions on the inside, usually made of tungsten or brass.

Counterfeit gold kilobar with embedded tungsten rod and gold cover

How to Quickly Verify the Authenticity of Bullion, Coins, and Thin Ingots?

There’re multiple destructive methods for checking the authenticity of bullion, coins, and thin metals. We cover them in detail in another article. However, those methods lead to a loss of value of a tested item.

The most reliable non-destructive method for identifying the fraudulent bulk precious metal is by checking its electrical conductivity.

All metal alloys differ in their electrical conductivity, making this physical dimension ideal for precise material determination.

Using Helmut Fischer’s Sigmascope Gold B or C, it’s possible to precisely tell if an item is authentic within a second, non-destructively, with just a single touch of a probe.

The Sigmascope Gold product line is ideally suited for determining the conductivity and authenticity from small precious metal coins up to large 400oz gold bars

The instruments use MS/m (mega siemens per meter) unit that is a widely acceptable electrical conductivity measurement. Each metal has a specific value. Here’s an example of electrical conductivity for several popular precious metals.

  • Ducat: 25.4 MS/m
  • Krugerrand: 9.7 MS/m
  • 975 coin gold: 8.0 MS/m
  • Pure gold: 45 MS/m

Electrical conductivity – a positive indicator for authenticity

Sigmascope Gold series work non-destructively and utilise eddy-current method according to ASTM E 1004. The phase-sensitive measurement signal evaluation allows for a contact-free determination of the electrical conductivity even under non-conducting top layers such as plastic packaging.

Testing gold bullion – even under a plastic cover

Testing coins – even under a plastic cover

The penetration depth of the eddy currents can be selected corresponding to the thickness of the specimen. When testing standard 400oz gold bars, it’s possible to probe the sample halfway through. Hence, to achieve full penetration, two opposing sides of the thick bulk precious metal have to be tested.

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