May 2022: The shop is currently closed for refurbishment so you'll find us next door - check out our Facebook page for updates!


  Learn more about us  

      Read our reviews      

      More recent work      

There is a lot of hype around moissanite at the moment, with this ultra-fashionable gemstone being touted as the new sustainable 'diamond alternative'. I have seen a lot of claims online about moissanite being an environmentally friendly option that is indistinguishable from a diamond, whilst being just as durable and having more sparkle. While there is no doubt that moissanite can be a lovely gemstone in its own right, these claims are misleading. There is a lot of 'smoke and mirrors' around moissanite in the jewellery industry, with dubious grading practices and inflated pricing. So, how do these claims stack up, and how does moissanite compare to diamonds?

Environmentally friendly?

Moissanite is described as environmentally friendly and sustainable because it is lab-grown. But all gemstones can be lab-grown these days, including diamonds. Therefore when comparing the eco-credentials of gemstones, it is important to compare like-for-like. Synthetic moissanite is no more eco-friendly than synthetic diamond, emerald or aquamarine. They are all produced in exactly the same way. If you want a more eco-friendly alternative to a natural diamond, the more logical choice would be a lab-grown diamond. However, even lab-grown gemstones have an environmental impact, using large amounts of electricity and water. For a truly sustainable and eco-friendly option, why not choose an antique diamond? There are some stunning old-cut stones available.


Most people know that diamonds are the hardest gemstone on earth, and can only be scratched by another diamond. They score a 10 on the Mohs scale, which rates the hardness of all minerals on a scale of 1 to 10 (with talc scoring 1). Moissanite scores around 9.25 on the scale, making it the second hardest gemstone after diamond - which is impressive. However, it is important to understand that the Mohs scale is non-linear, and there is a huge difference between 9 and 10. Diamond is many times harder than sapphire which scores a 9, and is very prone to scratching and wear with normal use. So while moissanite will be more durable than a sapphire, it is not as durable as a diamond.

Indistinguishable from diamond?

When moissanite became fashionable a few years ago, gemstone testing equipment wasn't calibrated to recognise it. This resulted in moissanite incorrectly testing as diamond (which was the closest match), and led to claims that the two were indistinguishable from one another. New testing equipment has been updated to allow for this, and moissanite no longer tests as diamond. But testing aside, it has always been possible for a jeweller to tell them apart with the naked eye. Moissanite tends to have a grey cast to it in certain lights. Diamond sparkles white with a hint of colour, but moissanite is much more reflective and has a 'disco ball' effect with rainbow sparkles, as can be seen in the image below. While this can be impressive, it just doesn't have the same 'look' as a real diamond. Check out this great video from Chris Bilton (formerly of Professional Jeweller Magazine) as he examines a moissanite stone for the first time. 

More sparkle?

As we explained above, moissanite certainly does have more sparkle than a diamond. This is because it is doubly refractive and shows much more fire and brilliance, giving the 'disco ball' effect. Some people love this ultra-flashy sparkle, and others think it looks 'fake' and brash compared to the subtle sparkle of a diamond. But the sparkle of any gemstone is down to its cut, and a perfectly cut diamond will out-sparkle a badly cut moissanite. And this is where the lack of an official grading system for moissanite can be a real disadvantage, as it's difficult for customers to know what they're getting.

Grading and quality

Everybody knows about the 4 Cs of diamonds - cut, colour, clarity and carat weight. The diamond grading system was developed by the GIA (Gemological Institute of America) in the 1950s and is still used worldwide today, both by the GIA and other grading services (such as IGI and EDR).

There is no such grading system for moissanite, but some unscrupulous sellers will give diamond-style gradings to their stones to make them seem more impressive. There is even a new moissanite certifier calling themselves the GRA, which issues grading certificates that have been designed to imitate the official GIA diamond grading reports. You can see Chris talking about this in his video, and a genuine GIA certificate is shown below. I agree with Chris - while it's great for gemstones to be graded by a reputable source, I'm not convinced the GRA is one of them. In addition to the copycat certificates, their website is extremely suspect and full of spelling errors. The site claims that "since 2001 GRA has been proven to be the internationally recognized passport for gemstones". I have never heard of them before, and neither have any of the other jewellers I asked. So be very careful parting with extra money for these 'GRA certified' stones. It is not possible to get a D colour VVS1 moissanite, because it doesn't exist - regardless of what the official-looking certificate says!  


There is no doubt about it - traditionally mined diamonds are very expensive. This is part of their appeal - they have an air of luxury and exclusivity. It is truly special to own something so rare and precious, billions of years in its creation and mined from the depths of the earth. Prices increase exponentially as you exceed 1ct, as it is much rarer to find gem-quality stones in these sizes. However, lab-grown diamonds are growing in popularity and can be bought for a fraction of the price, especially in larger sizes. These diamonds are created in a laboratory by mimicking the creation process of natural diamonds, but over the course of a few days rather than a few billion years. So while lab-grown diamonds might not have the elusive appeal of a natural diamond, both are 'real' diamonds and identical in every way - just like the ice in your freezer is the same as the ice in Alaska! Supply and demand simply means that these lab-grown diamonds are much cheaper than natural diamonds, and moissanite is a fraction of the price again.

For example, I recently quoted a customer for a 0.90ct GIA certified natural diamond in an E colour and SI1 clarity (6.3mm diameter). The RRP was £4,500. I also priced up a 1ct IGI certified lab-grown diamond in the same colour and clarity (6.5mm diameter), and the RRP for this was £2,250 - exactly half the price, for a larger stone. For comparison, a good quality 6.5mm moissanite can be bought for around £450. The 'GRA' certified stones seem to be more expensive, despite most of the grading scores being meaningless, because they relate to diamonds and not moissanite.


Moissanite jewellery definitely has its place, and a well-cut stone can be stunning. But it should be enjoyed for what it is - sparkly, inexpensive and fairly similar to a diamond. I find it concerning when I see moissanite being described as being 'exactly like a diamond', or being given a dubious certification to increase the price. Touting lab-grown moissanite as the 'sustainable alternative' to natural diamond is a stretch, when lab-grown diamond is clearly the more logical choice and offers the same environmental benefits. The lower cost is undoubtedly the main advantage of moissanite, but the prices are creeping up as more 'certified' stones hit the market, and they become more fashionable. If you do choose a buy moissanite jewellery, be sure to choose your jeweller carefully to ensure you are getting the best quality stone for the best possible price.