Back to Jewellery Blog

Can You Tell a Moissanite from a Diamond?

Date Added: 20/04/2019

Moissanite and diamond have visually similar characteristics so Moissanite commonly gets mistaken for diamond. Even experts confuse Moissanite for diamond!

We custom made a ring for a client in Melbourne which cost $2,500. Our client could not believe it when they took it to their local gemologist and valuer, and it came back valued at $28,000! The expert thought our Moissanite ring was a diamond. Moissanite even tests as a diamond with a diamond tester, due to the Carbon present in its chemical makeup.


Can you tell a Moissanite from a diamond with the naked eye?

No! Moissanite and diamond are indistinguishable from each other to the naked eye.

With huge advancements in technology, we are able to create far better quality Moissanite than ever before. SUPERNOVA Moissanite is the most natural looking Moissanite available because in sunlight, it has zero fluorescence and doesn’t show the undesired blue tint that can be seen in other Moissanite. These qualities, along with its stunning fire, makes Moissanite look like a high-quality fine diamond.

While the tests outlined below can give a good indication of whether a stone is a Moissanite or a diamond, they are not completely reliable.


How to tell the difference between a Moissanite and a Diamond

If you want to tell the difference between a Moissanite and a diamond, there are a few indicators to look out for. To see some of these features you will need specialised equipment such as a jeweller’s loupe, Moissanite tester or a JFIRE tester.


Double Refraction

The most effective way to tell Moissanite apart from a diamond is to use a loupe to look through the top, or the crown, of the jewel at an angle. If you know what to look for, you will see two slightly blurred lines that indicates a double refraction, an inherent quality of Moissanite.

Double refraction is easier to see in some shapes than others. For example, even an incredibly skilled jeweller with a loupe would find it difficult to see double refraction in an Emerald cut.

Our own SUPERNOVA Moissanite cut has been perfected to minimise double refraction, but still maintaining the brilliance of the jewel., so it’s becoming increasingly harder to see.



Moissanite is not as dense as a diamond, meaning a Moissanite will weigh slightly less than a diamond of the same size. To avoid confusion, the carat weight of Moissanite is always listed by its diamond equivalent carat weight. So you could weigh a Moissanite and Diamond of the same size and if one weight slightly less than the other, it could be an indication of a Moissanite. However, the difference in actual weight is extremely subtle, and the diamond could be cut shallower or deeper, so it is really hard to use this method of identifying Moissanite.

Furthermore, weight can only be used as an indication of whether a jewel is Moissanite or diamond when a stone has not been set. After a stone has been set, it is next to impossible to feel a difference in weight.


Moissanite and Diamond Testers

Diamond testers work on the principle that different jewels conduct heat differently. They measure the rate at which heat passes through the stone to determine whether the stone is a diamond or not.

Diamond and CZ can be easily differentiated from one another because they conduct heat in totally different ways. Moissanite and diamond conduct heat in very similar ways, so when checked with a diamond tester, both Moissanite and diamond are identified as a diamond. Moissanite testers were developed to distinguish the two gemstones from one another.

Moissanite testers work on a similar principle as diamond testers, but they use electrical conductivity to identify the stones based on their electrical properties.

While they can serve as a good indication of whether a jewel is Moissanite or diamond, Moissanite testers have been known to show incorrect results and are therefore not a completely reliable way tell Moissanite from diamond. It is sometimes very difficult to test smaller stones as well.


Polished Girdle

If you were to look at a diamond’s girdle at 40x magnification, you will see that it is faceted like the picture on the left. The girdle of a Moissanite can be polished, as shown on the right. A polished girdle can be an indicator of a Moissanite.

However, it’s becoming increasingly common to find Moissanite jewels with a faceted girdle, so this should only be used as an indication of whether a jewel is Moissanite or diamond.



JFIRE Tester

Moissanite has a higher refractive index than diamond which causes it to disperse more light than diamond. This is what gives Moissanite its signature fire and brilliance!

A JFIRE tester, pictured below, shows how a Moissanite and a diamond of similar size disperse light when suspended in water.

While a JFIRE tester can give an indication of whether a jewel is Moissanite or diamond, it requires you to have access to a JFIRE Tester and have a decent sized jewel to be unset, so this test cannot be performed on a finished piece of jewellery.



While the above tests can be a good indicator of whether a jewel is Moissanite or diamond, there is no definite way to differentiate these jewels from one another. To the naked eye, and even under a jeweller’s loupe, Moissanite and diamond can be difficult to differentiate.

Moissanite is a true alternative to diamond offering unrivalled beauty and incredible value.