Ask The Experts: Seven Ways To Spot A Fake Diamond

Making an investment in lifetime pieces like a diamond engagement rings requires reassurance. It would be devastating for a bride to know after years that her prized 6 carat diamond ring was nothing more than a fake. If you have received or inherited a gift of diamond jewellery, it’s understandable that you would at some point wonder whether they are real and natural diamonds, especially when ‘lab grown’ diamonds are now so commonplace.

Luckily, there are several ways to test whether a diamond is real, rather than a similar-looking imposter. We’ll take a depth look at some at-home tests and let you know which is the most reliable test to spot a fake diamond. To give you ultimate peace of mind, it can also be a good idea to visit to a jeweller for professional testing using their equipment.

Ask The Experts: Seven Ways To Spot A Fake Diamond

The Water Test:

The water test is considered as one of the easiest tests ever: all you need is a normal glass, filled three-quarters with water. Then, just pop the loose diamond into the glass.

  • Reaction of real diamonds: If your diamond is real, it will sink into the glass
  • Reaction of fake diamonds: If your centre stone is quartz, it will want to float, or at least stay at the water’s surface.

This test works because of the fundamental physical law of density – while diamond is more dense than water, quartz is not. One thing that can make this tricky is that you need a loose diamond, rather than one mounted in a ring.

Ask The Experts: Seven Ways To Spot A Fake Diamond

The Fog Test:

No equipment at all is needed to perform this one, other than yourself. Before you start though, it’s important to ensure that that the gem is clean as possible, as dirt and oil can affect the results.

Take a diamond ring or a diamond between the two fingers. Just like you did in childhood with a mirror to draw something to blow some air on the diamond.

  • Reaction of real diamonds: The fog will disappear immediately if the diamonds are real
  • Reaction of fake diamonds: There will be vapour for several seconds on the fake stone. For instance, moissanite keeps air on the surface of your bathroom mirror or sunglasses.

Among all the experiments to spot a real or fake diamond, the fog test is one of the most reliable. The test is valid as it has a scientific background: due to high conductivity, a real diamond can instantly disperse the heat, while other stones will not.


The scales test:

Diamond weight is measured in ‘carats’, and two diamonds with the same dimensions will always weight the same, while other  other precious and semi-precious stones will have different densities and will therefore weight different amounts at the same size. For example, cubic zirconia weighs around half as much as a diamond, while moissanite is around 15% lighter.

The scales test replies on you having access to two similar shaped gems, then weighing them together to see whether your stone is a real diamond. This may be most easily conducted by a jeweller who has access to verified diamonds and can compare to yours.

Ask The Experts: Seven Ways To Spot A Fake Diamond

The loupe test:

 A loupe is a tiny magnification device which can be used to examine the finest details on a precious stone. In the magnification test, a loupe can be used to identify a real diamond through a critical parameter in the 4C’s: Clarity.

If you wish to perform this test, get yourself a 10x magnification glass as the more accurate a loupe you have, the easier it is identify a real diamond from a fake. All diamonds have inclusions that are visible under a loupe, except for the very top clarity grades of ‘flawless’. If you examine your gem and can’t see tiny inclusions, it’s very likely that you are looking at something other than a diamond.


The Sparkle Test:

To double-check the diamond is real, you can observe the sparkling ability of your gemstone, paying special attention to the way it reflects the light. If it’s a real diamond it will demonstrate white sparkle from inside and then scatter it in rainbow colours. On the contrary, alternative stones like moissanite tend to intensify the rainbow reflection and deliver much more colourful sparkles.

Ask The Experts: Seven Ways To Spot A Fake Diamond

The Dot Test:

For the Dot test, you just require a piece of paper and a pen. Draw a dot on the piece of paper, and place the jewel from the flat ‘table’ side down on the dot. Look through the pointed side of the gem. If you can see even a crystal clear dot, it means your stone is likely fake. While, if you are unable to see anything, it’s much more likely that your gem stone is a real diamond.


The Black Light Test

A black light can be one of the most interesting ways to check if a diamond is real. To perform this test, turn off all the lights and put the diamonds under the source of a black light. If you witness an intense blue colour on the diamond’s surface, you are holding a genuine diamond. The blue is known as ‘fluorescence’ and is a result of boron present in the diamond itself. A fake diamond will reveal itself in other colours including yellow, green or grey sparkle.

Ask The Experts: Seven Ways To Spot A Fake Diamond



If in doubt, ask a professional

Many of these tests can help you to confirm whether your diamond is real or not. Because of the complexity of synthetic gemstones, we highly recommend you to visit your nearest diamond store where experts will be able to inspect and evaluate your gemstone. Using specialised equipment, an appraiser will be able to tell you whether your diamond is real or fake! Lastly, it’s important to ask for a grading report or certificate of authentication when you’re close to finishing your diamond hunt and making a purchase. It will provide peace of mind when you finally get down on one knee!






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