Cubic Zirconia vs Moissanite vs Diamond: What’s Better?


One of the best quotes from the FRIENDS hit series we all enjoyed is “friends don’t let friends wear bad outfits” and I may add or choose the wrong gemstone engagement ring.

Making a sound decision when it comes to jewelry is my mission and I’m happy to help you quickly find out the difference between cubic zirconia vs moissanite vs diamond gemstone in terms of quality and inherent value between them.

The main difference between zirconia (SZ), a real diamond, and moissanite stone lies in their ability to reflect light (brilliance), strength according to Moh’s scale as well as toughness, flawlessness or color, and sourcing (natural vs lab-made). Price and craftsmanship are the final key distinctions too.

Let us do what loveable Phoebe of FRIENDS usually tries, but fails to do and break down to you these three sought-after jewelry pieces in plain man’s term, even Rachel will fully understand after.

Diamond, Cubic Zirconia, and Moissanite Side by Side (Comparison Table)

Gemstone Hardness* Toughness** Brilliance*** Source**** Value
Diamond 10 3.4 2.417-2.419 Nature/Lab highest
Moissanite 9.5 7.6 2.42-2.69 Mostly Lab middle
Zirconium (SZ) 8-8.5 2.4 2.15-2.18 Mostly Lab lower

*Moh’s hardness scale measures gems from 1-10 ranges, whereby 10 is the hardest level.

**PSI measures the resistance to chipping or breaking in ascending order.

***Refractive Index measures return of light, the higher the metric number the better.

**** Gemstones are sourced either naturally or lab-created, most costly are nature-based.

As you can see:

The differences between a sparkling diamond engagement ring (brilliance) and its counterparts are as important as the other gemstone metrics like hardness, toughness, or origin of a stone.

If you want to determine which of these three you want to buy for yourself or as a gift to a significant other, then this gemstone chart is quite a handy tool. For a complete list on artificial precious gemstones, click here on my best fake diamond jewelry guide for money savers and fashionistas.

To solidify our findings, let’s do a simple data interpretation of the key metrics above:

Cubic Zirconia versus Moissanite versus Diamond (Hardness)

The distinction between a diamond with a hardness scale of perfect 10 and a moissanite stone (9.5) is minimal. Both gems possess a very high hardness scale, whereby a diamond is unbeatable.

On the other hand, we can see from the data that zirconia (SZ)  hardness is “only” 8 to 8.5. out of 10. This translates to a higher hardness range, though not as hard as the moissanite or natural diamond.

Verdict: The harder a gemstone, the better it resists e.g. external pressure. Here a real diamond is supreme, followed by moissanite, and last followed by cubic zirconia.

Cubic Zirconia versus Moissanite versus Diamond (Toughness)

According to the comparison table, moissanite is the toughest of the three stones (7.6 metrics) on the official PSI scale of toughness determining gemstones’ ability to withstand.

Next is a diamond with a 3.4 toughness and finally cubic zirconia rated at a low 2.4.

In other words, moissanite stands the best changes to withstand chipping and breaking, followed by diamond stones that is less than half as tough and zirconia (SZ) is the least tough of the three pieces of jewelry.

Cubic Zirconia versus Moissanite versus Diamond (Brilliance)

One of the main reasons a couple decides to buy sparkling wedding rings is because marriage is one of the most important decisions in their lifetime.

Which type of ring we eventually shop online or at a brick-and-mortar, depends on many times on the brilliance the gemstone returns when it reflects natural light.

Saying the magical words “I do”, therefore also relies on the brilliance of the stone atop the wedding ring. Well, that brilliance can be measured and compared to determine the quality of the stone. 

In terms of brilliance, we can establish that cubic zirconia provides the smallest amount of brilliancy, followed by the diamond and the most brilliant gemstone is moissanite.

The reason for this simply lies in the composition and source of these three types of gemstones which we will touch later on below.

Here’s a short answer though:

Verdict and Interpretation: Jewelry like these 3 gems is measured in their brilliancy as a form of diamond stone identification. A brilliant diamond may or may not possess flawlessness. 

Moissanite vs Diamond

A moissanite engagement ring is usually glowing more than a diamond. However, the distinction scientifically is mainly based on the brilliance scaling metric as well as subjective human perception.

Moissanite tends to be of quite a white hue but contains some rainbow effects when inspected closer by eyes and definitely true with a dichroscope that measures the speed of light through a gemstone and the light’s return (Source).

A regular diamond on the other is usually colorless and brilliant, showing no rainbow spectra whatsoever.

Zirconia (SZ) vs Diamond

At the end of the scaling and grading spectrum, we have a cubic zirconia jewelry ring that is typically the least brilliant, albeit being colorless like a diamond. Whereby through this type of colorlessness is interpreted as rather “superficial” by jewelry experts and certain consumers.

Verdict: The lower brilliancy of zirconia (SZ) indicates its origin and quality. It is a white stone that many people like since it shows no coloration outside the whitey coloration that can visually be detected.

Moreover, a real diamond necklace for example is of stunning brilliance, though might not be as bright as the next stone.

The gem with the highest brilliancy is for example a moissanite wedding band, though its drawback may lie in its inherent characteristic of resembling a rainbow when you lay your eyes on it a bit closer.

Cubic Zirconia versus Moissanite versus Diamond (Source)

These top three gemstones distinguish each other on a critical level outside the fore-mentioned criteria.

The origins of gemstones,  which partly determine its characteristics and retail value are consequently of major importance for the jewelry consumer before shopping for a precious earring, bracelet, or ring.

Real Diamonds versus Lab Diamond Side by Side

Type of Diamond How Made (Composition) Diamond Test Pass*
Real Diamond 100% Carbon Crystals (naturally mined) Yes
Lab-made Diamond 100% Carbon (manufactured in a lab) Yes
Moissanite Silicon Carbide (manufactured in a lab) Yes
Cubic Zirconia Zirconium Dioxide (manufactured in a lab) No, *using thermal conductor diamond test

What makes a real diamond?

Real diamonds are 100% made of reactive nonmetal carbon (C) which forms under extreme pressure as well as heat together and grow crystals. They are then mined and used for cutting the hardest materials as diamonds possess the hardest resistance (10/10) regarding Moh’s hardness scale.

How are lab diamonds manufactured?


A diamond is either mined in a minefield naturally or it is manufactured in a laboratory artificially. This results in different end products in terms of quality and pricing. Properties are basically equal to organic mine diamonds in terms of optics, chemical composition, or physics. 

The 4 C´s Grading System and Lab-created Diamonds

In short, lab-grown diamonds have the same properties as real ones and are therefore graded the same in terms of the four C´s diamond identification standard:

  • Color
  • Cut
  • Clarity
  • Carat

The rule of thumb is that, since diamonds are rare in nature the quality and price are higher than those which can be artificially reproduced eternally.

Pros and Cons of Lab Diamonds versus Real Diamonds

Benefits of Lab made Diamonds

Generally, we differentiate between three types of lab-created diamonds:

  • Lab-grown Diamonds,
  • Moissanite, and 
  • Cubic Zirconia (SZ)

All these three are considered lab-created diamonds that resemble a real mined diamond. The advantages are:

  • Diamonds created in specialized laboratory are cheaper than a real diamond dug from mines
  • A lab diamond looks like a real one to the average human eye
  • A simulant diamond can have positive characteristics equal to or sometimes better than real ones (e.g. clarity, no flawlessness like an organic diamond)
  • A lab grown gem diamond is not from conflict areas (e.g. blood diamonds)

Disadvantages of Lab-created Diamonds

  • These stones are considered of lower value and sometimes referred to as fake diamonds
  • The quality of a lab-made diamond (esp. cubic zirconia and to some extent moissanite) can be seen and experienced when exposed to the elements
  • Metallic inclusions contamination
  • Ultraviolet fluorescence and weak patterns of strain

Cubic Zirconia versus Moissanite versus Diamond (Value)

At the end of the day, naturally mined diamonds will always outperform lab-created ones in terms of durability, beauty (subjective), and most importantly value as the comparison clearly indicates the grades from highest to lowest.

You can always resell your mined natural diamond at a pawn shop, online or elsewhere. Whereas only high-quality moissanite earrings, bands, pendant necklaces, or rings can achieve an acceptable resale price.

A zirconia (SZ) choker will mostly never get its retail price back, not even at 90% knockoff. The value is rather sentimentally than inherently here since diamond simulants like cubic zirconia are not a scarce commodity in high demand like real mined diamonds.

The modern jewelry fashion trend is nonetheless more and more offering interesting designs like customized wedding engagement rings to opal bangles or birthstone name pendants with diamond imitates like moissanite or pure lab diamond.

Not fine jewelry diamond, but nearly as spectacular looking like that shinning solitaire on white gold – at a much lower rate as 90% (moissanite) in comparison to an expensive brilliant ring.

Cubic Zirconia versus Moissanite versus Diamond (Final Verdict)

Although zirconia (SZ), as well as the moissanite gem, can be found and mined in nature, there are very rare and it is not really worth it (Source).

Therefore, these two diamond imitates are mostly manufactured at laboratories artificially. This is also true for diamonds. They exist under the earth like zirconia or moissanite and are at the same time being extensively mined worldwide, from South Africa to Russia and beyond.

However, real diamonds are difficult to mine as they require numerous resources before unearthing, and they are limited in amount.

This increases their market price and perceived value even higher, though the De Beers diamond cartel doesn’t exist anymore that used to control the market worldwide.

Are lab-created diamonds worth anything? 

Lab-grown stones are an inexpensive diamond alternative though still higher in value than a moissanite gem which is not made of carbon, nevertheless still goes through a difficult manufacturing process that has its price (Source).

Cubic zirconia is the cheapest of them because it is not made out of carbon like – mined, lab diamonds, or moissanite stones. However zirconia (SZ) resembles the appearance of a flawless diamond, at least depending on who exactly you ask.

Cubic zirconia vs diamond engagement rings is therefore not really the question since they both possess optical commonalities as well as fine distinctions.

Depending on perspective and gem expertise (e.g. CZ won’t pass a diamond tester as seen in the above table).

A classic real diamond still stands the test of time. Whereas moissanite is a great alternative simulant and the cubic zirconium gem looks like the most affordable synthetic diamond of all.

Even Phoebe and Rachel are now inclined to pick one depending on taste and budget.

What about you on the best gemstone – prefer real sparkling diamond ring setting, artificial and budget-friendly cubic zirconia or flawless white necklace or rainbow brilliant moissanite birthstone jewelry?

Bill Dominic

Bill is an art history and business graduate. Moreover, he loves to test, compare, shop jewelry & fashion items for his 5 sisters, girlfriend, nieces when not enjoying a great novel.

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