Cubic zirconia and moissanite are two popular lab-created diamond simulants on the market. While they might look alike at first glance, there’s a lot that differentiates the two. Let’s take a look at these differences and which is the better diamond simulant.
Cubic Zirconia vs. Moissanite
2 carat cubic zirconia engagement ring with matching diamond wedding band.
Moissanite engagement ring by Charles and Colvard.
Both cubic zirconia and moissanite are natural gemstones that are so rare in nature that they can only be found in their synthetic state. Of the two, moissanite is older, discovered in 1893 while cubic zirconia was discovered relatively recently in the 1930s.
1- Chemical Composition
In terms of chemical composition, cubic zirconia is the crystalline form of zirconium dioxide (ZrO2) while moissanite is made from silicon carbide (SiC), a combination of silicon and carbon. As diamond is made of pure carbon, moissanite is closer to diamond in terms of its chemical make-up compared to cubic zirconia.
2- Interaction with Light
A perfectly cut cubic zirconia stone.
Diamonds are so valued because of their ability to refract light and sparkle like no other gemstone. However, moissanite has a much higher refractive index (the measure of a gemstone’s brilliance) than a diamond and very high level of fire (a.k.a. dispersion of light) known as the ‘rainbow effect’ of moissanite.
Cubic zirconia has a lower level of fire and brilliance than moissanite and doesn’t display the same amount of intense flashes of color that moissanite can sometimes exhibit. Of the two, moissanite has a deeper, more captivating sparkle.
This video shows a comparison of a moissanite and cubic zirconia ring side by side. The stone on the top is the moissanite. It’s almost impossible to tell them apart!
For engagement rings or jewelry meant to be worn frequently, durability is an important issue. Cubic zirconia ranks at 8 to 8.5 on the Mohs scale, which is similar to aquamarine, morganite or beryl. While it’s easy to maintain and clean, over time, cubic zirconia can become discolored or cloudy and get scratches that affect its sparkle.
Moissanite, on the other hand, has a Mohs ranking of 9.25, which is higher than all gemstones except diamond. This makes it the second hardest gemstone used in jewelry. They’re highly heat resistant and can withstand even the ravages of a fire. Moissanite is also tougher than cubic zirconia, with a resistance to chipping that’s over 3 times that of CZ. However, moissanite can acquire what’s known as the moissanite oil slick, a colorful oily looking stain on the stone. This can be washed off and isn’t known to be permanent.
While both stones are much more affordable than diamonds, moissanite falls into the mid-range while cubic zirconia falls into the cheap category. Compare these two rings that have a similar look:
Both are around the same size and are set in solid 14k white gold settings. But the difference in price is almost $1600!
Moissanite is much more expensive than cubic zirconia because making it takes up time and resources. It’s much harder to create, requiring high tech equipment and expertise. There’s also a resale value when you buy moissanite whereas CZ is worthless if you want to sell it down the track. If you’re decision is guided by budget, then CZ is the best option for you but if you want a stone with more value, moissanite is the way to go.
Cubic zirconia is always perfectly colorless and has the D color grade of a diamond. It can also be colored to show different hues like red, yellow, blue, black and so on.
Moissanite comes only in colorless, although sometimes you can also find it in blue and green. In the past, moissanite tended to have some green, gray or yellow tints and was rarely perfectly colorless, but with improvements in technology, the quality of moissanite color as increased.
Cubic zirconia is flawless and shows no inclusions or imperfections. Moissanite, on the other hand, often has some structural flaws and shows some tiny imperfections, very much like natural diamonds. This can be considered a plus point though, as too much perfection can look fake. It’s the tiny flaws that make a stone look natural.
Should I Buy a Cubic Zirconia or a Moissanite?
Both these stones are diamond simulants, so if you’re highly traditional and you care what people think, going with a diamond might be your best option. For some people, it doesn’t get better than a diamond (even though this social consciousness is largely created by marketing efforts of the diamond industry).
However, if you’re after a practical, financially smart option, a cubic zirconia or moissanite could have a lot to offer.
If budget is the most important to you, choose a cubic zirconia. It looks so much like a real diamond that only a gemologist with special tools would be able to look and tell you it’s not real.
If your budget allows, and you’re after a stone that’s unique in its own right, with exceptional durability and beauty, then a moissanite could be just what you’re looking for.