How to tell if a diamond is real or fake

A diamond is a girl's best friend, but if it turns out to be a fake, it may well become her enemy. Diamonds don't come cheap, so discovering that what you've bought isn't the real deal, not only signifies you've been ripped off, but the disappointment will be insurmountable.

Fortunately, there are lots of ways to tell whether a diamond is a fake or not, and many of these tests you can easily do yourself.

Examine the diamond

A small magnifying glass, called a loupe, can be instrumental in your quest to discover the authenticity of your stone. When you examine it under the loupe you should be looking for small imperfections, called inclusions. Diamonds are natural, so even if you can't see these minute flaws with the naked eye, they should be visible under the loupe. If your stone looks perfect with no flaws, chances are it isn't a real diamond. Bear in mind, though, that some of the most sought-after diamonds with the highest price tags can be completely flawless, so don't rely on this test alone.

Take a look at the edges of the stone whilst examining it. Diamonds have sharp edges, so if your stone has rounded edges, it's unfortunately not the real deal.

Light reflection

A diamond should sparkle grey and white inside, whilst throwing off flashes of colour, known as fire. If you notice rainbow reflections within the stone, there's a strong chance it's not a diamond.

Light refraction

Diamonds refract and bend light sharply, which gives them their sparkling brilliance. If your stone isn't a diamond, it will have lower refractive qualities so won't sparkle as much. You can study a stone's light refraction by placing it over a newspaper. You shouldn't be able to see any of the newspaper type through the stone, if it's a diamond. If your stone is mounted, and you can't see through it to the mount, this also indicates that it's a diamond.

Fog test

Real diamonds don't retain heat, so one way to tell if yours is genuine or not is by breathing hot air onto it. A real diamond will not fog up, whilst a fake will, even for a few seconds.

Mounting and etchings

A genuine diamond will not have been mounted with a poor quality metal, so use this as a clue to determine whether your stone is fake or not. A diamond is more likely to be mounted in gold or platinum, rather than gold plated or silver, so check out the setting stamp of the stone. Examine how well the diamond is set, also. If it looks of high quality, there's a good chance you've got a diamond.

Rub it with sandpaper

Diamonds are extremely tough and can easily withstand the slightest scratch. If you want to check to determine if your stone is actually a diamond, rub it with sandpaper. If it doesn't scratch, it's a diamond.

X-ray examination

If you're really serious about knowing the true identity of your stone, consider getting it x-ray tested at a professional diamond testing laboratory. Because of the molecular structure of a diamond, it won't show up on an x-ray image, whilst other types of stone such as cubic zirconium will.

Not all of the diamond tests may be 100% accurate on their own, so it's worth conducting a few of them, to glean a more accurate picture. Alternatively, get an expert gemologist to examine your diamond for you.

If it's not a diamond, what could it be?

There are various types of stones that mimic diamonds at first glance, so understanding what these could be can help you to identify whether your diamond is genuine or not.

Cubic zirconium

A common diamond substitute, cubic zirconium is distinguished by the way it shines. It often projects an orange shine or a variety of colours when exposed to light, which is not the case with a diamond. Under close inspection, cubic zirconium also has a clear appearance, and is devoid of inclusions, which are inherent in a diamond.

White topaz

Easy to mistake for a diamond, white topaz is actually a much softer material than diamond, so is prone to scratching.

White sapphire

White sapphire differs from a diamond in that it doesn't have a sharp and sparkling contrast between light and dark areas. You can often spot this if the stone has an icy or somewhat hazy appearance.


Moissanite and diamonds are often easily mistaken for each other, but moissanites tend to be sparklier than diamonds, with a double refraction.

Synthetic diamonds

You can buy diamonds that are not natural but have been created in a lab. Synthetic diamonds normally cost a fraction of the price compared to real diamonds, but because it can be hard to tell the difference, it's wise to get a trained expert to make a distinction for you.

Avoiding a fake

If you want to buy a diamond, naturally, you won't want anything less, so make sure you avoid the risks of receiving a fake, in the first place. Always shop at a reputable jewellery store, such as Albone, and ask for a certificate or paperwork that proves that the diamond is the real deal. Don't be afraid to ask questions about the diamond and its quality. A good jeweller should be able to talk through the different characteristics of the diamond with you, or its four Cs - clarity, colour, carat and cut - so you get an appreciation of exactly what you're buying.

As well as making sure you buy from a reputable jewellery store, if you want to get your diamond professionally tested, choose where you do this with care. Some high street jewellery chain stores may not have the required expertise to carry this out for you, so consider using the services of an independent jeweller or gemologist, particularly if you are interested in finding out how much your diamond might be worth.