Your cart

Your cart is empty

How to tell a real diamond from a fake

How to tell a real diamond from a fake

What is a fake diamond?

A fake diamond is a stone that has a different chemical composition to real diamonds. They are also known as diamond simulants, faux diamonds and diamond imitations. Fake diamonds may be artificial, natural, or a combination of the two. On first glance, they may even display similar characteristics to those of a diamond. Such as light dispersion and hardness, lending themselves to diamond imitation.

The most common faux diamonds are moissanite, white sapphire, and cubic zirconia. They closely resemble a diamond in terms of physical properties and appearance. The best imitators are those that are hard like diamonds, and that are reasonably clear and colourless. Each of these stones are beautiful alternatives to diamonds, differing greatly in price, meaning that they are a more affordable choice. 

There are many simple and effective ways to tell a real diamond from a fake, from home testing methods to a close glance. It is recommended that if you are unsure about a diamond's genuineness, that you visit Sonny's Jewellers in-store for an in depth insight into your stone. Our team will be happy to analyse your jewellery and provide more details about its quality and provenance.  

Home testing methods

The fog test 

This is an easy and safe home testing method that works for both diamond jewellery and loose diamonds. You start by holding up your diamond or jewellery piece between two fingers and lightly blowing or breathing onto the diamond. How the diamond reacts to you doing this will determine its authenticity. 

A key characteristic of diamonds is that they are good heat conductors, meaning that they disperse heat easily. Therefore, it is more difficult for them to become fogged up. On the surface of a real diamond, the fog can disappear quickly. 

You will be able to spot a fake diamond if the vapour holds for a lengthy period of time, just like when your glasses or bathroom mirror fogs up. 

The water test

The water test is one of the easiest home methods used to help spot a fake diamond. It works by measuring the density of a loose stone, using a simple law of physics. 

You can do this test by filling a glass with water and dropping a loose diamond into it. Due to the high density of the stone, a real diamond will drop to the bottom of the glass. However, if the diamond is fake, you may see it float on, or underneath the surface of the water. 

The fire test

Another method that you can use to determine whether your diamond is real or fake is by fire testing, a test that should only be done on loose diamonds. Before you do this test, it is important to consider the safety precautions, and ensure that you are clear of any flammable materials, and that you have access to fireproof gloves to avoid getting burnt. 

Using a lighter, gently heat the diamond for around 30-40 seconds before dropping it into a glass of cold water. Real diamonds are formed under intense heat and pressure, and therefore, when the heated diamond falls into the water, it will have no reaction, and remain unharmed in its current state. 

Due to the weak structure of a fake diamond, this method can shatter it, as its materials may not be able to withstand the intensity of the heat. This can indicate that the diamond is not real. 


How to tell if a diamond is real


Visual tips for telling if a diamond is real


Observe the sparkle 

For the sparkle check, all you need is your eyes! It could be argued that the most endearing part of a diamond is its exceptional sparkle. By observing the brilliant shimmers of light that bounce off of the diamond, you will be able to identify the distinguishing features of this precious stone.

Diamonds have an elegant sparkle that reflects a white light. Pay close attention to the way that the light is reflected. Diamonds sparkle white light from the inside and scatter this into rainbow colours whereas fake diamonds intensify this rainbow-coloured reflection, with no presence of white or grey light.

You will be able to tell a huge difference in the sparkle of a fake and a real diamond, making this an effective way to gain a better understanding about your diamond. 

Check the mount of the diamond

If your diamond is already set into a piece of jewellery, then you can use the mount to tell whether or not it is real. Diamonds are a precious, valuable stone, and therefore, only set in high quality metals, such as platinum, yellow gold, white gold and rose gold. If your piece displays the correct markings on the mount, then this might reassure you of the legitimacy of your diamond. 

For platinum, the markings PT and karat will be present, whereas for gold, you will see 10K, 14K or 18K markings, which indicates what type of gold is used. If you see numbers such as 585, 770, 900, and 950, this also shows that these precious metals have been used. However, if you find a C.Z cubic zirconia note, or a .925 silver marking, then the diamond is more likely to be fake.

Use a magnifying glass

Diamond clarity is graded on the scale of slightly included to flawless. This is based on the size, and amount of imperfections within the stone. By taking a magnifying glass or a loupe, you can look closely to see if there are any imperfections within your stone. 

If you are unable to see any imperfections, there is a high possibility that it is fake. Diamonds that are flawless in clarity are extremely rare, and the one's that do possess this quality are typically lab-grown or very pricey. The majority of real diamonds have flaws, so if you do spot inclusions, then you may have a real diamond on your hands. 

Even though using a magnifying glass will give you an insight into the genuineness of your diamond, it may be unreliable as a single method of testing for a real or fake stone. This is because not finding any inclusions could mean that your diamond is fake, but there is also a small possibility that the stone could be lab-grown or in fact, flawless. You may have a very valuable stone! It is recommended that this test is carried out alongside others and that if you are still unsure, you should consult a professional jeweller for advice.


GIA Diamond Chart


GIA Diamond Certification 

If your diamond or diamond jewellery has a GIA Diamond Grading Report, then you know that your diamond is real. This will give a detailed and accurate description of your diamond’s quality, grading and of anything that the diamond has undergone, such as improving its clarity or colour. To find out more about the GIA certification of diamonds, read the GIA guide and our 4C's for Diamonds Guide

Evaluating your diamond 

The most accurate way to tell if your diamond is real is by heading to your local jewellers, who will complete thorough tests on your stone. Here at Sonny's Jewellers, we will be happy to evaluate your diamond, and provide you with the answer to your question. Get in touch with us today. We welcome any queries and look forward to hearing from you. 

Back to Sonny's Jewellers Blog