How can you tell if a diamond is real?

How can you tell if a diamond is real?

Trying to decipher whether a diamond is real or fake? Bring in any diamonds you may have to our Hatton Garden store – here, we’ll professionally assess them to see if they are real or fake. Our staff will be happy to help. 

While jewellers or gemologists will use professional ways of telling if a diamond is real such as using electric conductivity, a loupe, high profile weighting, a microscope or an x-ray examination, it’s unlikely that you’ll have these tools at home.

However, there are multiple home tests you can conduct on your diamond to tell if it’s a real or a fake! 

How to tell if a diamond is real at home


Princess cut Diamond Ring in 4 Claw Setting

A simple test to check if a diamond is fake or real? By using trusty H20. Fill up a glass about three quarters of the way up with water and drop in the loose stone. You’ll be able to tell if the diamond is real as it will sink. If your loose stone floats underneath the surface of the water, it’s a fake. From a physics perspective, diamonds have high density, meaning that they should sink to the bottom. 

Magnifying glass

Simply, use a magnifying glass to inspect your stone closely. Notice any imperfections? It’s likely that your stone is real – as fake diamonds are often made without imperfections, while real diamonds’ imperfections are referred to as ‘inclusions’. Find out more from our diamond buying guide.

You can also use your magnifying glass to check the setting and mount – a real diamond will likely be set in materials such as platinum, white gold or pave. Look inside the ring’s centre for the ring markings – these markings refer to the material that has been used to create the stone. If you see CZ, for example, this refers to Cubic Zirconia – which is a fake diamond.


Not using the mirror for its reflection, but for its durability, this home scratch test should indicate whether a diamond is real or not. Scrape your loose gemstone along the side of a mirror to see whether it scratches the glass. Generally, if the mirror is scratched, it suggests the diamond is real. However, fakes which are formed strong materials can also be very durable – so it’s worth using another test alongside this one to determine is your diamond is real.



Round Cut Trilogy Diamond Ring


Place the loose stone in front of your mouth and breath on it until it fogs up. A sure-fire way to tell if a diamond is fake is how quickly the stone fogs up – if it won’t fog up easily, it’s likely to be real, as the condensation doesn’t stick to the surface. If it fogs up within a few seconds, it’s probably a fake.

Blacklight/UV light

Pretty simple as long as you have a blacklight or a UV light, but begin by turning off all the lights, turn the UV light on in front of the diamond. The UV light on a real diamond should normally show a strong-medium shade of blue fluorescent colour – however, on a fake diamond, you may see a light green, yellow or grey. It’s important to note that not all diamonds will show a blue colour and may not glow under a blacklight or a UV light – so it’s recommended you also use another test to prove if your diamond is real.


In a bright room with no figures or objects casting shadows, place the stone flat side down onto a page of newspaper (preferably during a section which lots of wording). If you can read letters from the newspaper through the diamond, even if it’s blurry and illegible, the diamond is a fake. If the diamond is real, it will reflect the light in different directions, meaning you won’t be able to clearly see through the stone. 

If you don’t have a newspaper to hand, you could try using the ‘dot test’ instead. Following a similar procedure to the test above, draw small dots on a white piece of paper. A true diamond has powerful refractive qualities, so if you can see the dot or a circular reflection through the gemstone, it is a fake.



Oval & pear cut 3 Stone Diamond Ring

How to check if a diamond is real

Our detailed guide highlights only but a few ways to tell if your diamond is fake. There are extensive, multiple ways which can often prove inaccurate due to the number and complexity of synthetic gemstone materials. Therefore, we recommend you consult a diamond expert, such as Shining Diamonds. Visit our Hatton Garden store today.

 We will be able to offer advice and information on how to tell if a diamond is real. Get in touch with a member of our expert team today.