Moissanite vs. Cubic Zirconia, which looks most like diamond?

Moissanite vs. Cubic Zirconia: A Sparkling Showdown

We were recently asked, which diamond simulant, Moissanite or cubic zirconia looks most like a real diamond?

We understand, when it comes to choosing a gemstone for your jewelry, the decision can be overwhelming. In this article we will answer the question – on the sparkling showdown of moissanite vs. cubic zirconia – which looks most like a natural diamond.

Moreover, for the sake of completeness we will also discuss other factors you should consider when comparing cubic zirconia with moissanite. These factors are cost, durability, and appearance. Let’s get started.

What is Moissanite?

Moissanite is a gemstone that was first discovered in a meteor crater in Arizona by Dr. Henri Moissan in 1893. Initially, he thought he had found diamonds, but later realized that the crystals were composed of silicon carbide. Today, virtually all moissanite is lab-created, making it a sustainable and ethical choice for jewelry.

Moissanite is known for its high refractive index, which gives it exceptional brilliance and fire (the dispersion of light into colors).   Moissanite is also a very hard gemstone, ranking 9.25 on the Mohs scale of hardness.   In comparison Diamond, the hardest natural material that we know of is rated at 10.   Rubies and Sapphires are a 9 on Mohs Scale.   So, Moissanite is a durable choice for everyday wear.

What is Cubic Zirconia?

Cubic Zirconia, often abbreviated as CZ, is a synthetic gemstone that has been used in jewelry since the 1970s.   

Cubic zirconia was purposely created to imitate diamond.   According to IGS, an authority on gemstones, cubic zirconia is made of zirconium dioxide (ZrO2).  The cubic part of the name comes from the fact that the stone has a cubic crystalline form.   Diamonds also have a cubic crystalline form, so cubic zirconia is a great diamond lookalike.   Lab created CZ tends to be flawless with an excellent clarity rating and lack of color.  In fact, most high quality CZ have a GIA diamond color grade of D, which is the highest rating given for diamond color.

Cubic Zirconia ranks 8.5 on the Mohs scale of hardness, making it less durable than moissanite.  However, CZ is still a hard gemstone being hard enough to scratch glass.  As such CZ is great for jewelry, though perhaps better suited to occasional wear in rings.

PHOTO:   Because of its low cost, durability and close visual likeness to diamond, CZ is widely considered as one of the best faux diamonds.   Seen above is a 3 carat cz solitaire ring from Luxuria.

Moissanite vs. Cubic Zirconia

When comparing moissanite vs. cubic zirconia, there are several factors to consider.

Cost

Cubic Zirconia is significantly less expensive than moissanite.   Typically cz is less than 1/10^th of the price of Moissanite.   One carat of high quality moissanite can retail for around $400 while a similar sized CZ will cost around $10 to $40.  This is because the process to create cubic zirconia is less complex and more cost-effective than the process to create moissanite.

Value

As both cubic zirconia and moissanite are lab-created, neither are rare.    The value of gemstones comes down to scarcity.   Great works of art and diamonds are high-value assets by their scarcity.    Burmese rubies are far more valuable than diamonds because they are much rarer.    When comparing moissanite vs. cubic zirconia you should note that neither have meaningful resale value.

Durability

As mentioned earlier, moissanite is more durable than cubic zirconia.  This makes moissanite a better choice for jewelry that will be worn daily, such as engagement rings.  When comparing cubic zirconia with Moissanite,  Moissanite is much more resistant to breaking, chipping or scratches.

Brilliance

Both moissanite and cubic zirconia have high refractive indexes (RI), giving them exceptional brilliance.  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 and CZ at 2.18.   This means moissanite has a higher dispersion of light, giving it much more fire than natural diamond.    

Appearance : Moissanite vs Cubic Zirconia

So, back to the original question.   Which diamond simulant, Moissanite or cubic zirconia looks most like a real diamond?

The answer surprisingly is high grade cubic zirconia.   Below we outline two reasons why high grade cubic zirconia more closely resembles natural diamond in appearance than Moissanite.  

The problem with Moissanite is Dispersion

When light hits a gemstone and reflects, you see a sparkle and a prism of colors.   These colors are known as fire.  The gemological term for this is dispersion.    Moissanite’s fire exceeds that of diamond, ruby, sapphire and emerald, as well as other popular gemstones including CZ.   As a scientific measurement, moissanite’s dispersion is 0.104, which means it has 2.4 times the fire of a diamond at 0.044.

Simply put, Moissanite is a more fiery stone than both diamond and CZ.  This means Moissanite will produce more colorful sparkles than a similar diamond would produce.   With over twice the dispersion of diamond, some feel moissanite resembles a disco ball.   Furthermore, it’s fiery nature is a dead giveaway that Moissanite is not diamond. 

In contrast the dispersion of CZ is 0.06 and thus much closer to a natural diamond.

PHOTO:   Comparing cubic zirconia with moissanite.   Moissanites high dispersion creates a colourful ‘disco ball’ kind of effect as seen LEFT.   In contrast, while CZ is not as brilliant as Moissanite its refractive index (RI) and dispersion (fire) measurements are closer to a natural diamond.   Further Grade 6A Hearts & Arrows CZ seen RIGHT has high levels of optical cut precision typically reserved for the top 1% of natural diamonds. 

Moissanite is rarely colorless

Moissanite is a near colourless gem, whereas high grade diamonds and CZ are colourless.  

Under certain lighting conditions and angles it is very easy to see that Moissanite is not colorless.    Colored overtones are very evident, even to the naked eye.  On an overcast day, many moissanite engagement rings will have a slight grey hint to them.  In other lighting conditions Moissanite may have a green, pinkish or yellowish hue.  

Although the GIA’s scale does not officially grade Moissanite or cubic zirconia,  jewelers will use the scale to communicate a stone’s color and clarity.   According to GIA the color grading scale begins with the letter D.   This represents colorless.  The scale continues with increasing presence of color to the letter Z, representing light yellow, light brown or light gray.

According to IGS, like diamond, cubic zirconia is naturally colorless.  In fact, most natural diamonds have a faint yellow or brown tint.  Cubic zirconia is completely clear, comparable to a D color rating.   In contrast, Moissanite is rarely colorless with many being in the G to I color range.

Moissanite’s light management differs to Diamond

Moissanite has a refractive index from 2.65 – 2.69, which is much higher than a diamond.  Moissanites handle light differently from diamond, creating what is termed as “birefringance”.  Basically, light waves are split inside the crystal and their velocity becomes unequal, thus things appear doubled in appearance.

The end result is that Moissanite does not look identical to a diamond.   When examined closely, diamonds emit a combination of colorless sparkle (centre), rainbow sparkle (edges), and flashes of white light.   Moissanite look different.   When you rotate a Moissanite stone the emission is more of a ‘rainbow effect’ while diamonds reflect whiter light.

This ‘rainbow effect’ is only heightened when the size of the Moissanite stone increases.  If realism is important to you then when considering fake diamonds we suggest you keep stone sizes relatively small.

TABLE:   Moissanite vs diamond vs cubic zirconia.  A technical comparison of diamond versus common diamond simulants, both naturally occurring, and lab created.      

Summing it up: Moissanite vs. Cubic Zirconia

Both Moissanite and cubic zirconia are affordable alternatives to diamond.   Moissanite and cubic zirconia are not the same as real diamonds.   That said, to the naked eye, their optical qualities make it difficult to tell the three gemstones apart.

When comparing moissanite vs. cubic zirconia, there are several factors to consider.   These factors are cost, value, durability, and brilliance.

Cubic zirconia wins on cost.   Its less than 1/10^th of the price of similar sized moissanite.

There is no clear winner for value.  Both CZ and Moissanite are lab created so neither stone has scarcity.   Accordingly neither can be considered as an investment and both have no real resale value.

Moissanite is the clear winner of durability.   Lab created moissanite is an exceptionally hard stone and ideal for daily wear.   Moissanite has a high resistance to damage and abrasion.

Which looks the closest to Diamond,  Moissanite or CZ?

If close visual likeness to diamond is the most important consideration then opt for CZ.  Why?   The objective answer comes down to two measures; dispersion (fire) and color.

Dispersion is Moissanites weakness.    Scientifically, moissanite has over twice the dispersion value of diamond.   This creates a disco ball kind of effect with the stone rather than the whiter flashes associated with a diamond.   Some shoppers like this fire or ‘rainbow effect’ and think it looks beautiful while others think it looks fake and cheap.   Personal preferences aside, Moissanite does not sparkle the same way as diamond.   In contrast, the measured dispersion of CZ is much closer to diamond.

Stone color is another difference between Moissanite and diamond.   Moissanite is rarely colorless or transparent.   Moissanite stones usually have a tint of green, gray or yellow and these colored overtones can vary according to angle and lighting conditions.   According to Carl A. Jones, a GIA Graduate Gemologist (GIA GG) and founder of the Diamond Market Insider Authority, it is impossible to get the moissanite pure white.  He adds that it’s not uncommon for people to love the moissanite when they see it in the jewelry shop and then really dislike it once they get out of the store and see it in natural light.    In contrast, while incredibly expensive, diamonds with a GIA D color rating are colorless.   Furthermore, cubic zirconia is completely clear / pure white, comparable to diamonds D color rating.

Conclusion – Consider Grade 6A CZ

In conclusion, in the sparkling contest of moissanite vs. cubic zirconia, if close visual likeness to diamond is the most important consideration we recommend Grade 6A CZ.   For round stones insist on Grade 6A H&A stones. 

Hearts and Arrows diamond simulants (“H&A”) are precision-cut variations of the traditional 57 faceted round brilliant cut.    The optical symmetry of the dark arrows creates an exaggerated contrast and distinction between the whiter areas and the darker areas.  This helps create “white flashes” much like real diamond does.

While only a diamond looks exactly like a diamond, simulants like CZ and Moissanite have a close visual likeness.   In the contest of moissanite vs. cubic zirconia, which you choose depends on which factors; cost, durability or appearance are most important to you.   We hope you found this article comparing cubic zirconia with moissanite useful and encourage further reading referenced below.

About Us & Further Reading

Luxuria® Diamonds is a designer and marketer of diamond simulant and gemstone (natural and synthetic) engagement rings.   Luxuria is a professional member of the International Gem Society (IGS), USA.

Interested in reading more about different types of fake diamonds?   Read our authority post titled “What Are The Best Fake Diamonds?”

Much confusion exists on the topic of simulated vs synthetic diamonds.  Read our educational article entitled “Diamonds Simulants & Synthetics – Differences Explained”