Gold verification methods

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Here you will find answers to the following questions:

1. What are the methods of verifying gold?
2. How do you check if a bar is authentic?
3. How does a magnetic balance work?
4. How does a Fisch ruler work?
5. How do you check the density of gold?
6. What methods does Goldsaver use to verify bars?

At a glance

• Gold purchased from reputable dealers is verified before sale – its authenticity is checked by professionals, which is confirmed by the certificate issued.
• There are a number of tests that, thanks to the specific properties of gold, will distinguish pure bullion from counterfeit.
• Gold bars and coins are checked by comparing dimension and weight and testing the product on a magnetic balance. You can also use an ultrasonic test, an electrical conductivity test or a sound test.

Basic verification of gold

The basic test for the authenticity of bars and coins is to compare the weight and dimensions with the parameters indicated by the manufacturer. Gold is dense. It is very difficult to fake the dimension of a bar or coin while maintaining its weight. Usually, if the weight agrees, the counterfeit coin has a different dimension than that indicated by the manufacturer. To check this, all you need is a scale and a caliper.

The popular Fisch Ruler is also based on the same principle. The ruler allows you to check the correctness of the weight of a one-ounce coin and its dimension (holes have been cut for the basic bullion coins, which exactly match the manufacturers’ dimensions). With the ruler we will check only the top 1 ounce coins. There are sometimes rulers produced by other companies, which can deceive us (they are simply not so precise). We recommend that in such cases we should be cautious, and supplement verification with a ruler with other methods.

Checking that the weight and dimensions match the manufacturer’s description is a basic step. In some cases, it may not be sufficient.

At home, you can try a verification based on Archimedes’ law, i.e. use a home water balance (place gold on a thread, submerged in water). This method requires calculating the mass of water displaced. In this way, we will examine the density of gold. It is the density that is one of those specific properties of gold that makes it difficult to make counterfeits.

Magnetism

A popular test for all gold products is the magnet test. We can use this method on various gold products with a homemade magnet. Gold is diamagnetic. This means that it is minimally repelled by a magnet. If the magnet attracts the object, we can be sure that it is not pure gold.

Counterfeiting of gold investment products can involve the use of tungsten. There is less gold in a bar filled with tungsten than its weight would indicate. Tungsten has a density similar to gold, but it is a paramagnet, meaning that it is attracted to a small degree by a magnet. Approaching an undersized magnet to pure gold products, we should feel a slight resistance.

Magnetic scales

For products such as a bar or coin, a more accurate measurement based on these properties will be a magnetic balance. It is much more precise and indicates exactly with what force and in what direction (attraction or repulsion) there is a relationship between the magnet and the object under test. Scale manufacturers include tables with the values that should be obtained when testing individual coins and bars.

Importantly, this method also makes it possible to verify the authenticity of bars in certipacks. A professional magnetic scale with a certificate is available at any Goldenmark chain store. The gold verification service is free of charge.

Sound

The sound test is a method worth trying on bullion coins. A light tap on the edge of the coin will produce a characteristic sonorous sound. The other metal will produce a dull, deafening sound. Sound recordings to compare with the sound of the coin can be found on Youtube or use one of the many apps for your phone. The sound method does not require any specialized tools, so it has been known for thousands of years. It is based on differences in resonant frequencies.

Ultrasound

Ultrasound, or ultrasound, allows you to obtain an image that shows the differentiation of structures in the object under examination – that is, if there is a metal other than gold inside the bar, you will see it on the screen. Analogous to the ultrasound method used in medicine, which allows non-invasive diagnosis of internal organs. The ultrasound examination uses different speeds of sound waves passing through different structures (in the case of the examination of bars – through different metals).

Ultrasound, however, will not check bars in certipacks.

Electrical conductivity

Tungsten used to counterfeit gold can also be detected using an electrical conductivity test. It is extremely different for the two metals – gold is an excellent conductor of electricity (conductivity of 44 megasiemens per meter), while tungsten is a poor conductor (only 18 MS/m). The test is performed with a conductivity meter. The test is possible up to 17 mm in depth. It will not work for larger products, such as large bars.

In this list we omit methods that involve examining the surface of an object – spectrometer or X-ray fluorescence. Not only do they require specialized equipment, but most importantly they examine the surface itself. A spectrometer will work only for thin objects.

The most versatile method is to use a magnetic balance (we will examine both bars and coins this way), this examination should be combined with verification of the basic weight, dimensions and an overall assessment of the conformity of the product’s workmanship to the manufacturer’s parameters. It is prudent to always use 2-3 verification methods. For example, for coins made of pure 24K gold, a density test, supplemented by a sound test, will work well.