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What is a 6.5 mm Moissanite in Carats?


Browsing for Moissanite engagement rings and other moissanite jewelry you'll most likely find the size of the moissanite given in millimeter (mm) unlike diamonds which are sized in carat (ct). Why is that? This is because moissanite have a lower density than diamonds and thus weigh less whilst having the same volume.  

So how much carats is a 6.5 mm Moissanite exactly?

Moissanite weighs approximately 15%-18% less than diamonds. Talking about a 6.5 mm moissanite most people mean a round cut moissanite. This cut and size is also the most common one you will find in many jewelry shops and also on our website.

A 6.5mm round cut moissanite has 0.88 carats and equals a 1 carat diamond in size.

Because moissanite is a highly sought after diamond alternative and both beloved by manufacturers and customers the size is either shown in millimeter or ctw which means "total carat weight" and represents the weight of a same sized diamond. Resulting in a smoother shopping experience.

But there’s more!

Millimeter to Carat Conversion Varies with Cutting Shape

Congratulations! Now you know that a 6.5mm moissanite equals 1 ctw but that only applies to round cut moissanite! A 6.5mm cushion cut moissanite already equals 1.5 ctw same as a princess cut moissanite and a pear cut Moissanite equals 1ctw at 5x8mm.

8mm pear cut moissanite in carats?

Moissanite vs Diamond Size Comparison Chart

Complicated? Don't worry! We prepared this moissanite to diamond conversion table where you can easily and at one glance find all the answers you need!


Round Brilliant Cut 8 Hearts 8 Arrows - 58 Facets 

 Moissanite Size (mm) Diamond Equivalent Weight (DEW in ct)
3.0 0.11
3.5 0.17
4.0 0.25
4.5 0.36
5.0 0.50
5.5 0.66
5.75 0.75
6.0 0.84
6.5 1.00
6.8 1.25
7.0 1.30
7.5 1.67
8.0 2.00
8.5 2.43
9.0 3.00
9.5 3.35
10.0 4.00
10.5 4.20
11.0 5.00
12.0 6.00
14.0 10.00

Shop Loose Round Cut Moissanite

Now that you’re armed with knowledge in moissanite sizing
 your engagement ring shopping has become a little easier! As always, be sure to check out our website and follow our socials to keep up with the latest news of the shining world of the moissanite.

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