Ultimate Guide: How to Test Gold? Acid, Magnet & Electronic Methods

Determining the authenticity of gold has been a conundrum for centuries. With its lustrous appeal and substantial value, ensuring you’ve got the real deal is more important than ever. Whether you’re a curious collector, an eager enthusiast, or simply want to verify your jewellery’s worth, knowing how to test gold effectively is key.

Thankfully, there are several methods at your disposal, from traditional acid tests to modern electronic gadgets. Each technique offers its own set of advantages, catering to different needs and levels of accuracy. Let’s jump into the world of gold testing, where precision meets the eye’s delight.

Acid Testing

Acid testing is one of the oldest and most reliable methods for assessing gold’s authenticity. This technique indulges in using nitric acid and aqua regia to reveal the true nature of the metal in question. It’s a straightforward process, but it requires a cautious approach due to the hazardous chemicals involved.

Professionals typically use a testing kit that includes a black stone, also known as a touchstone, and several bottles of nitric acid at different concentrations. The gold item is rubbed against the stone to leave a streak or mark. Drops of acid are then applied to the mark. The reaction between the acid and the gold – or lack thereof – indicates the gold’s purity. No reaction signifies high purity, whereas a change in color or dissolving mark points to lower purity or counterfeit materials.

Even though its accuracy, acid testing has limitations. It can slightly damage the tested items, making it less ideal for finished products like jewellery. Also, it requires a skilled operator to interpret the results correctly. For enthusiasts or professionals looking to verify the authenticity of gold, being well-versed in acid testing is immensely valuable, offering a balance between traditional craftsmanship and scientific precision.

Magnet Test

Moving from the traditional acid tests to simpler, non-destructive methods, the magnet test stands out for its simplicity and immediate results. This test leverages the fact that gold is not magnetic. So, if a piece of jewellery or any gold item is attracted to a magnet, it’s a clear indicator that it’s not pure gold. But, it’s crucial to note that this method isn’t foolproof. Many base metals used in counterfeit gold products are also non-magnetic, meaning a lack of attraction doesn’t guarantee authenticity.

For optimal results, use a strong neodymium magnet. These magnets are significantly more powerful than regular magnets and can detect even slight magnetic properties in alloyed gold. To perform the test, simply bring the magnet close to the item in question. If there’s no attraction, it’s not a definitive sign of gold’s authenticity but rather a preliminary indication that further testing is necessary.

It’s essential to understand the magnet test’s limitations. Not all fake gold items contain magnetic metals, and some genuine gold pieces have magnetic clasps or components added for functionality, which could lead to misleading results. Hence, while the magnet test is a great initial step in authenticity verification, it should be part of a broader testing strategy to determine gold purity.

Density Test

Another reliable method to assess the authenticity of gold is the Density Test. Gold is known for its high density; hence, by comparing the density of an item with that of pure gold, one can gauge its purity. The process involves first weighing the gold item, then measuring the volume of water it displaces when submerged.

To perform this test accurately, a scale sensitive enough to measure small differences in weight is essential. The formula to calculate density is mass divided by volume. Since pure gold has a density of approximately 19.32 g/cm³, deviations from this figure can indicate the presence of other metals or materials.

Here’s a quick guide to conducting the density test:

  • Weigh the gold item.
  • Fill a graduated cylinder with water and record the initial volume.
  • Submerge the gold item in the water and note the new volume.
  • Calculate the change in volume, which represents the item’s volume.
  • Use the formula (mass/volume) to determine the density.

While the density test is more precise than the magnet test, it requires careful measurement and calculation. It’s also important to remember complex items with hollow parts may not yield accurate results due to trapped air. Hence, while effective, the density test is ideally used alongside other verification methods to ensure the highest accuracy in determining gold purity.

Electronic Testers

Electronic testers offer a modern and non-invasive method to test gold purity. These devices work by sending a small, harmless electrical current through the gold item. The resistance to this current correlates with the gold’s purity, providing a fast and accurate measurement. Unlike acid tests, electronic testers do not require any physical alteration or damage to the item, making them an attractive option for testing precious gold items.

They come in various models, from handheld pens to more sophisticated benchtop devices. While the handheld versions are excellent for quick verifications and portability, benchtop models provide more detailed analysis and are often used in professional settings.

It’s important to note, but, that the accuracy of electronic testers can vary depending on the model and the skill of the user. It’s advisable to refer to the manufacturer’s instructions closely and, if possible, calibrate the tester before use. Even though their convenience, they should still be part of a broader strategy of gold authentication, employing multiple methods to ensure the most accurate result.

One key advantage of these devices is their ability to test gold without causing harm, making them ideal for appraising valuable or antique gold pieces where preserving condition is crucial.


Testing the authenticity of gold requires a strategic approach combining traditional and modern methods. From the classic acid and magnet tests to the more precise density test, each offers valuable insights into gold purity. But, they’re most effective when used together for a comprehensive evaluation. Electronic testers, with their non-invasive technique, bring a modern twist to gold testing, offering convenience without compromising the item’s condition. Whether it’s a cherished heirloom or a recent purchase, ensuring gold’s authenticity demands a careful blend of these methods. Remember, accuracy in testing not only protects investments but also preserves the timeless value of gold.

Frequently Asked Questions

What are the limitations of acid tests for gold authenticity?

Acid tests, though traditional, have limitations. They can be hazardous due to the chemicals used and may cause damage to the gold piece being tested. Plus, the results might not always be conclusive, particularly for gold items with complex compositions.

How does the magnet test work in testing gold?

The magnet test is simple: gold is not magnetic, so if an item is attracted to a magnet, it’s likely not pure gold. However, this test isn’t foolproof as some non-gold items may not be magnetic, and genuine gold pieces may have magnetic materials added for functionality.

Can the magnet test conclusively determine gold’s authenticity?

No, the magnet test can provide a preliminary indication but is not conclusive. Some counterfeit gold items may not contain magnetic metals, and genuine gold pieces may have magnetic components. It’s best used as part of a broader testing strategy.

What makes the Density Test more precise in determining gold purity?

The Density Test compares the item’s density with that of pure gold. It involves precisely measuring the gold item’s weight and the volume of water it displaces. This method is more precise than the magnet test but requires accurate measurement and calculation.

How do electronic testers determine the purity of gold?

Electronic testers measure gold purity by sending a small electrical current through the item and measuring the resistance. The results can help determine the item’s purity. The accuracy of these testers varies, so it’s important to follow the manufacturer’s instructions and calibrate the device when possible.

Why should electronic testers be used as part of a broader testing strategy?

Although convenient and non-invasive, electronic testers’ accuracy can vary. They should be used alongside other testing methods to ensure the most accurate determination of gold purity, especially since they do not damage the gold and are suitable for valuable or antique items.