Buying a diamond is a huge decision. It can get very expensive and for that reason you want it to last a lifetime. It’s best, then, to ensure you’re buying a real diamond before you make the purchase.

If you’ve already bought it, and are having some doubts about its authenticity, worry not because there are some way you can determine this.

Don’t get caught out by diamond replacements such as cubic zirconia or moissanite, and ensure you don’t have a fake on your hands using these tests:

– The water test

A diamond has high density, so it shouldn’t float in water. All you need to do is fill a glass with water and drop the diamond in. If it floats, it’s fake.

– The fire test

Use a lighter to heat the gem for no less than 30 seconds, then drop it into ice-cold water. If the stone remains unharmed then it’s real and if not then it’s fake. Weaker materials cannot handle the rate of expansion and contraction that’s provided through this test. A diamond, however, will withstand it.

– The fog test

This one is quick and easy. Hold the diamond close to your mouth and try to fog it up. If it stays fogged for more than 4 seconds, it’s likely that it’s fake. This is because diamonds disperse heat easily, which means it’s quite difficult to fog up.

For this test to work, your stone has to be completely clean with no oils covering it.

– Black light test 

Of course you’ll need a black light for this test. Turn off the lights, shut the curtains and hold the stone in front of the black light. Most diamonds will reveal blue fluorescence. If you see slight green, yellow, or grey, your diamond is fake. It’s important to remember that for this test, that not all diamonds will reveal blue fluorescence.

– Imperfections test 

Look at your gem through a magnifying glass. If you don’t find imperfections, you have a fake on your hands. A real diamond will have imperfections, referred to as inclusions.

– The dot test

Draw a small dot on a white piece of paper and put the stone onto the dot, with the flat side down. Looking through the pointed side of the diamond, try to see the dot. If you see a circular reflection, the diamond is fake.

Diamonds have strong refractive qualities. Therefore, light bounces around in all directions instead of in a straight line. Because of this, you won’t be able to see the dot through a real diamond.

It’s important to remember that these tests are not 100% conclusive. If you’re still unsure by the end of these tests, then the best option is to head over to a diamond expert who will have the necessary equipment to investigate.

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