Verifying moissanite means confirming it, not catching it out
Moissanite is a real gemstone. It is silicon carbide, a crystal with its own optical and physical properties. When you verify a moissanite, you are not checking whether a stone is a fake diamond. You are confirming that your stone is genuine moissanite and that it matches the grade on its certificate. That is a different job from diamond verification, and it uses different tools. This guide explains how to do it with confidence, using the paperwork and methods that apply to every stone we supply. If you want the background first, read is moissanite a real gemstone and what is moissanite.
Start with the GRA certificate
Every MER SA moissanite ships with a GRA certificate. GRA stands for Gemological Research Association, and its report is the standard grading document for moissanite. The certificate records the shape, the carat weight, the measurements, the colour grade, the clarity grade, the cut and a unique report number. This is your first and most useful verification step. Read the certificate and check that the details describe the stone in your hand. A 6.5mm round stone on paper should measure close to 6.5mm across when you look at it. To understand how GRA sits alongside diamond reports, read our GRA vs IGI vs GIA certificate guide.
Find the laser inscription
Most certified moissanite carries a laser inscription on the girdle, the thin edge that runs around the widest part of the stone. The inscription is tiny and you will need magnification to read it, such as a jeweller's loupe. It usually carries the report number that matches the GRA certificate. When the number on the girdle matches the number on the paper, you have linked your physical stone to its grading report. That link is the strongest everyday proof of authenticity you can hold.
Why a basic diamond tester says not diamond
A common worry is that a diamond tester at a jeweller reads moissanite as not diamond. This is expected and it is a good thing. A basic diamond tester measures thermal conductivity, which is how quickly a stone moves heat. Diamond and moissanite conduct heat differently, so a thermal tester built only for diamond will not confirm moissanite. It is doing exactly what it should. Moissanite is intentionally its own stone. It is not pretending to be diamond, so a diamond-only tool will not treat it as one. We cover this in detail in does moissanite pass a diamond tester.
Use a combined tester for a clear answer
The accurate tool is a combined moissanite and diamond tester, sometimes called a multi-tester. It measures electrical conductivity as well as heat. Moissanite conducts electricity in a way diamond does not, so the combined tester can tell you plainly that a stone is moissanite. If you take your ring to a jeweller for a check, ask them to use a combined tester rather than a diamond-only one. For more on this, see can you tell moissanite from diamond.
Double refraction and fire
Moissanite is doubly refractive. Light splits into two rays as it passes through the stone. Diamond is singly refractive, so it does not do this. If you look through the top of a moissanite at an angle under magnification, you can sometimes see a slight doubling of the facet edges at the back of the stone. This is normal and it is one of the ways gemmologists identify moissanite. Moissanite also has high dispersion, which is the rainbow flash of colour known as fire. Its refractive index is about 2.65, higher than diamond, which is part of why it sparkles the way it does. These are features of the gemstone, not flaws.
Hardness and durability
Moissanite sits at 9.25 on the Mohs scale of hardness. That places it among the hardest materials used in jewellery, below diamond but above most other stones. High hardness means strong resistance to scratching in daily wear. You do not need to test hardness yourself, and we do not recommend scratch tests on any set stone. The Mohs figure simply tells you the stone is built for a lifetime ring.
Confirm your MER SA stone matches its report
Bringing it together is simple. Match the report number on the GRA certificate to the laser inscription on the girdle. Check that the shape, size and weight on the certificate match the stone. If you want an instrument check, use a combined moissanite tester. If you want a professional opinion, any qualified gemmologist can identify moissanite using magnification and a multi-tester. You can read more about how we document every stone on our certification and authenticity page. If you are still choosing a ring, browse our moissanite engagement rings or start a quote, and message us any time on WhatsApp at +27 69 288 1535.
Is moissanite a real stone or a fake diamond?
Moissanite is a real gemstone made of silicon carbide. It is not a fake diamond. It has its own optical and physical properties and its own grading standard through GRA.
Why did a jeweller's diamond tester say my moissanite is not a diamond?
Because it is not a diamond, and the tester is correct. A basic diamond tester only reads thermal conductivity. Ask for a combined moissanite and diamond tester, which reads electrical conductivity too and identifies moissanite clearly.
Where do I find the certificate number on my stone?
Look at the girdle, the thin edge around the widest part of the stone, under magnification. Most certified moissanite carries a laser inscription there with the report number that matches your GRA certificate.
Can I verify my moissanite at home?
You can do the most important check at home by matching your GRA certificate details and report number to the stone. For an instrument reading you need a combined moissanite tester, which many jewellers have.
Does every MER SA moissanite come with a certificate?
Yes. Every MER SA moissanite ships with its GRA certificate recording the grade and a unique report number.