Cubic Zirconia Hardness – What is the Mohs scale of CZ?

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While it is considered the next-best thing (alternative) to natural diamonds, cubic zirconia (CZ) is not as hard as the diamonds.

But that doesn’t mean that it is a soft stone either – If it were, it wouldn’t be considered a great alternative to the diamond.

So, just how hard is CZ, and how durable is it compared to diamonds and other materials often used in jewelry making?

Before we look at the details of its hardness, let’s first look at its basics.


About Cubic Zirconia

Cubic Zirconia Hardness

Cubic zirconia or CZ can be defined as one of the excellent quality alternatives to diamonds. Unlike natural diamonds, the CZ used in the jewelry industry today is artificial, and it is considered a cheap, durable, and brilliant alternative to diamonds.

The first CZ was created in the 1970s by Russian scientists, and after many years it is one of the best alternatives to diamonds.CZ boasts the same chemical features as diamonds.

The two could easily confuse each other, mainly because of their high level of brilliance and spark that is almost unrecognizable from that of natural diamonds.

These two stones are not the same, with the CZ stones being slightly heavier than the diamonds. More specifically, the CZ stones weigh 1.7 times more than diamonds, but they are not as hard as the diamonds.

Cubic Zirconia Hardness

The main features that make CZ stand out include the fact that this lab-made gemstone is created from a chemical compound called zirconium oxide that undergoes heating at very high temperature and pressure conditions, hence the high-quality stones boasting a maximum degree of reflectivity.

These stones are graded differently than diamonds, but also, the stones are classified based on the 4Cs that determine the qualities of the stone.

Like diamonds, CZ is classified based on their cuts, clarity level, color, and carat weight. CZ stones are also graded on a scale ranging from I to VI, and this classification points to their quality and pricing.

CZ stones are also available in different cuts and colors, all thanks to diverse technologies. Some of these stones are transparent, but there are also many other CZ stones in rich colors and tones, and often, you will find CZ stones in transparent colors, white, pink, and champagne stones, among other colors.

Cubic Zirconia Hardness

The primary colors of CZ range from black to colorless, with lilac, pink, red, orange, yellow, brown, green, and blue being the standard colors on the CZ spectrum.

But are the CZ stones that cheap? The fact that these stones are made in the lab means that they are often believed to be the cheapest stones used in jewelry making, but this is further from the truth.

The stigma associated with cheap stones is non-existent, and the high-quality grade VI CZ stones are not the cheapest CZ stones you will spend your money on.

Even the highest quality CZ stones do not cost as much as genuine diamonds.


Cubic Zirconia Hardness- What is the Mohs scale of CZ?

Cubic Zirconia Hardness

The Mohs scale of hardness ranks minerals’ hardness on a scale of 1 to 10, with the materials on the lowest end of the spectrum being the stones that are easy to scratch and fragile, while the materials rated on the other end of the spectrum are the hardest and the most durable. This scale ranks materials from their ability to be scratched by other materials.

On this scale, diamonds are ranked 10, while Talc is rated a 1.0. Then you have CZ, whose hardness rates from 8.0-8.5. Thanks to the hardness of the stone or the cut crystals, the hardness ensures that the crystals remain sharp.

The CZ stones will show off polishing marks on the polish directions. The high hardness level of CZ means that the stone is quite durable, and it’s a significant investment in terms of affordable jewelry.

Note that the 5A CZ, also called the AAAAA-Graded CZ, is ranked 8.5 on the Mohs scale of hardness,  which is below the hardness of sapphires and rubies.


Does cubic zirconia scratch easily? How long can it last?

Cubic Zirconia Hardness

Although CZ is quite durable, CZ crystals can get scratched. So, despite its hardness, anything harder than it will potentially scratch it and leave scars on its surface.

As mentioned above, its hardness level is between 8 and 8.5, which means that it is quite scratch-resistant.

Still, it will be scratched by materials ranked higher above it, for example, diamonds, Alexandrite, Chrysoberyl, Cat’s Eye, Moissanite, Corundum, sapphire, ruby, tungsten carbide, the scratch-proof glass used in watches, emery board like fingernail files, and other diamond-coated drills or files.


Is cubic zirconia as hard as a natural diamond?

No, CZ stones are not as hard as the natural diamonds, with stones’ hardness of 8-8.5 and 10, for CZ and diamonds, respectively.

Cubic Zirconia Hardness

Is cubic zirconia harder than steel?

Yes, CZ’s hardness is between 8.0 and 8.5, while hardened steel ranks lower at 7.5 and stainless steel at 6.5.

On the other hand, plain steel is ranked 5.0 on the Mohs scale of hardness. With this in mind, CZ will easily scratch the surface of steel materials.

Cubic Zirconia Hardness

Is cubic zirconia harder than glass?

While the hardness of CZ ranges from 8 to 8.5 against the hardest material, diamond is ranked a 10, and glass is ranked a 5.5 on the Mohs scale of hardness.

So, if you place a CZ stone against the glass, the CZ will scratch the glass, and it is advisable to keep these two materials apart from each other.



Cubic zirconia is a high-quality lab-made gemstone with a hardness of between 8.0 and 8.5 on the Mohs hardness scale.

It is internally flawless, which means it is quite brilliant and makes the most attractive jewelry pieces.

This stunning piece makes it easier for you to stun in a diamond-like piece, but for much less than the natural diamonds.

It is pretty durable, though, and though it may get dull after some time, it only gets scratched by higher materials than on the Mohs scale.

And thanks to the A-grading system, the CZ stones used in jewelry making are all priced differently, meaning that there is something for everyone.

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