Moissanite vs. Diamonds: What's the Difference?

Dec 20th 2022

If you or your bride to-be are considering a moissanite stone for your engagement ring, you’ve got excellent taste! Moissanite rings are a classic diamond alternative that have been loved by many for so many years- and with good reason! Despite being visually similar to an earth mined diamond, there are a few differences that may cause a number of questions to arise. One of those questions may be the sizing difference between moissanite engagement rings and earth mined diamond engagement rings, as it can be confusing. In this blog, we’ll cover the difference between a moissanite millimeter and a diamond carat as well as how to convert the two.


Moissanite vs. Earth Diamonds 

Before touching on the measurement differences, we should first differentiate between what a moissanite gemstone is versus an earth stone. A moissanite gemstone, also known as a “diamond alternative” is one that’s cultivated in a lab, but is modeled after a naturally occurring diamond. The differentiating factors between the two are durability, brilliance, color, and price. Choosing a moissanite engagement ring is not only a smart choice price-wise, but it also comes conflict-free compared to the mining that takes place for earth diamonds. However, despite costing less than an earth diamond, a moissanite gemstone looks just as real to the naked eye.


The Measurement Difference 

You may experience some confusion as you start shopping for moissanite engagement rings due to the difference in measurements. Unlike typical earth diamonds that are measured by carats, a moissanite stone is typically advertised by a measurement in millimeters. This is due to a moissanite stone being 10% lighter in weight compared to earth diamonds, and rather than measuring the gemstone by carats like a traditional diamond, a moissanite’s size is categorized by length (millimeters). It is still possible, however, to advertise a moissanite ring by carats, but usually many moissanite engagement ring gemstones are labeled by millimeters. We’ve created a chart that compares a round moissanite ring length to the carat weight in a diamond that you can refer to when exploring your ring options. Keep in mind that the moissanite sizes may differ depending on which ring cut you choose!


Moissanite vs. Diamond Sizing Chart 

Moissanite Size (MM)Diamond Equivalent Weight (CT)
1 mm0.0025 ct
2 mm0.03 ct
3 mm0.11 ct
4 mm0.25 ct
5 mm0.50 ct
6 mm0.84 ct
6.5 mm1 ct
7 mm1.30 ct
8 mm2 ct
9 mm2.75 ct
10 mm3.87 ct

Following this chart, you’ll be able to accurately compare any kind of moissanite gemstone to its equivalent in carats. No matter what kind of ring you choose, we can promise it’ll sparkle as brightly as your love. If you need extra assistance on how to do so, or if you’d like to see what moissanite engagement rings we have in store, contact us today!

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