Jewelry Guide

Moissanite vs. Cubic Zirconia (CZ) – Which Is the Better Diamond Simulant?

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When it comes to engagement rings, diamonds are most people’s first choice but they come with a steep price tag and are beyond the reach most of us. The best way to have the diamond look without the cost is to opt for a diamond simulant.

A diamond simulant imitates the appearance of a diamond but is different in every other way. Although the first diamond simulant was the natural gemstone zircon, today the most popular are the lab-created cubic zirconia (CZ) and moissanite.

You might be wondering:

Of these two, which is the better diamond simulant? Let’s take a look at the pros and cons of cubic zirconia vs. moissanite to see which is the better option.

Moissanite Vs Cubic Zirconia side by side

Moissanite vs. Cubic Zirconia – History and Origin

Natural moissanite was first discovered by Henri Moissan (hence moissanite) in 1893 in Arizona. It is believed that the crystals had been brought to earth on a meteor that crashed into the site several thousands of years ago. As a result, moissanite is sometimes called stardust or space diamond. Moissanite is composed of silicon carbide, with the chemical formula SiC.

 Colorless moissanite gemstone. 

Natural cubic zirconia was only discovered in the 1930s. It is composed of zirconium oxide. Cubic zirconia contains a mix of zirconium and oxygen in its composition whereas moissanite is made of silicon and carbon. In this regard, moissanite is similar to diamond, which is composed of pure carbon.

Cubic zirconia round stone

Round brilliant cubic zirconia. See it here.

Both moissanite and cubic zirconia are extremely rare in their natural state. As a result, all moissanite and CZ on the market today are lab-created.

Winner: Moissanite. Its origin in the stars gives it an added romance and mystery and its composition is closer to diamond than CZ.

Moissanite vs. Cubic Zirconia – Durability

Diamonds are the hardest gemstone with a perfect ranking of 10 on the Mohs scale. But moissanite comes pretty close. It is the second hardest gemstone used in jewelry after diamonds ranking at 9.25.

This makes moissanite an exceptionally hard stone and ideal for daily wear. It has a high resistance to damage and abrasion.

A moissanite engagement ring will not easily scratch or damage.

Moissanite is perfect for engagement rings, which need to be hard-wearing and scratch resistant due to the excessive exposure they receive every day. Moissanites are more heat resistant than even diamonds, meaning that even if they were in a fire, they would still retain their sparkle and form.

Cubic zirconia is a hard stone but not as tough as moissanite.

Cubic zirconia is also a hard stone, ranking at 8 to 8.5. This makes it a good option for daily wear, just like moissanite as it is durable and scratch resistant.

However, in terms of toughness, which refers to the gemstone’s resistance to breaking, moissanite is much tougher than CZ. Moissanite has a toughness rating of 7.6 PSI while CZ is only 2.4 PSI. This means that moissanite is over 3 times resistant to breaking or chipping than CZ.

Winner: Moissanite. It is harder than CZ by 1.25 points and three times tougher.

Moissanite vs. Cubic Zirconia – Reaction to Dirt

Over time, with the accumulation of dirt and grime, both moissanite and CZ can take on a cloudy, hazy appearance. This can come from household detergents, cosmetics, body oils and dust and so on causing the stones to lose their sparkle and appear dull.

Moissanite is better able to resist dirt as opposed to CZ. CZ clouds over easily and loses its sparkle at a faster rate. It will need to be cleaned much more frequently than moissanite in order to keep it shining.

Winner: Moissanite. It is easier to clean and maintain.

Moissanite vs. Cubic Zirconia – Value

Compared to diamonds, both moissanite and cubic zirconia are much more affordable. However, moissanite is often much more expensive than cubic zirconia. A high quality moissanite carat can retail for around $400 while a similar sized CZ will cost around $20 to $40. Cubic zirconia is generally worthless and has no resale value.

This often surprises shoppers who tend to think of moissanite as a ‘fake’ diamond. They expect it to be much lower in cost than it is. It’s important to remember that moissanite is a stone in its own right and requires state-of-the-art technology, expertise and a high cost to synthesize it. It only costs about 10% of the price of a diamond. Compare this 1 carat marquise cut diamond with this similar 1 carat marquise cut moissanite.  As you can see, the moissanite is almost 90% less expensive than the diamond.

If you’re thinking in terms of investment, moissanite has an edge over CZ as moissanite it has retained its value over the past decades.

Winner: CZ. It is a much cheaper option and is very easy on your wallet. But moissanite has a better resale value.

Moissanite vs. Cubic Zirconia – Light Performance

The RI of a gemstone measures the amount of light that is bent as it goes through the gemstone and is an indicator of the gemstone’s brilliance.

Moissanite has a Refractive Index (RI) of 2.65 whereas diamond’s RI is lower at 2.42. Moissanite has an extremely high level of brilliance and excellent light performance. This is one reason it is a favorite in engagement rings as it has much higher brilliance and fire than a diamond.

moissanite vs diamond dispersion

The fire (dispersion) of moissanite is much higher than diamonds.

The flip side is that moissanite often gives off a fiery flash of colors, which is noticeable especially under sunlight. This isn’t prominent in smaller moissanite stones, but the larger the stone is, the more pronounced this effect can become. Shoppers are often divided on how they feel about the rainbow effect, with some finding it gaudy and others loving the colorful sparkle. This rainbow effect is one main distinguishing feature between diamonds and moissanite.

moissanite brilliance

Moissanite’s sparkle sometimes contains colorful tints.

Cubic zirconia has an RI 2.15 – 2.18, which is much lower than moissanite.  Although CZ has a good amount of sparkle and brilliance, it is not at the depth of that of a moissanite. CZ can sometimes appear glassy and lacks the fire of diamonds and moissanites. Its sparkle is often described as being more superficial.

Winner: Moissanite wins for brilliance but may lose for the rainbow effect (depending on how you feel about it). We’ll let you decide this one.

Moissanite vs. Cubic Zirconia – Color and Clarity

CZ is almost always created to be perfect and flawless, with an excellent clarity rating and lack of color. In fact, all cubic zirconia stones have a color grade of D, which is the highest rating given for diamond color.

cubic zirconia pendant

Cubic zirconia pendant with perfect clarity and color. See it on Helzberg.

Moissanite, on the other hand, is rarely completely white or totally transparent. They can contain certain greenish, grayish or yellowish tints and even some structural flaws. This is due to the complicated process involved in the production of moissanite. Like diamonds, which are never perfect, moissanites also contain internal flaws and miniscule imperfections.

Winner: CZ is almost always flawless in color and clarity. BUT this can cause it to look unnatural. Again, we’ll let you decide this round too.

Where to Buy Diamonds and CZ  Online

Although moissanite is less valuable than diamonds, they are still an expensive purchase.

  • Always purchase from a trusted source, check customer reviews prior to purchase and note the after-sales policies, especially returns policies.
  • Because moissanite does not come with a lab report, it’s important to purchase from a reputable company to avoid being ripped off.
  • Ensure that there are videos and images of the actual stone to assess its light performance.

For moissanite, Charles and Colvard stand out as the best in the industry and the first to have synthesized moissanite,  with an established reputation for providing high-quality moissanite gemstones and moissanite jewelry.. Read our comprehensive review on Charles and Colvard here.

Many retail shops offer beautiful cubic zirconia jewelry. Because CZ is considered a ‘cheap’ alternative to diamonds, retailers sometimes try to fool their shoppers by saying that they sell ‘zirconium oxide’ stones and NOT cubic zirconia. But zirconium oxide IS cubic zirconia so don’t get ripped off by these marketing tactics.

CZ comes in a range of prices, from a few dollars to hundreds of dollars. Amazon’s cubic zirconia jewelry collection has a wide variety of CZ jewelry and also features some amazing CZ engagement rings to choose from.

The Final Verdict…

Although CZ is a more affordable choice, we would have to choose moissanite as the better diamond simulant of the two, owing to its durability, brilliance and value.

In terms of prestige and class, nothing can take the place of a diamond, but moissanite comes close. CZ, unfortunately, will always be considered inexpensive and of little value.

When deciding between the two, lay down your budget and your priorities. And chances are no one would ever know the difference. At a glance, diamonds, moissanite and cubic zirconia all look alike.

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