blue topaz & cubic zirconia ring

Cubic Zirconia vs Diamond Side by Side Comparison

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blue topaz & cubic zirconia ring

Choosing an engagement ring is not a light task!

There are many different stones to choose from.

Two of the most popular options are diamond and cubic zirconia rings.

They look so similar that you can easily get confused.

  • Does cubic zirconia shine like a diamond?
  • What are the visual differences between diamond and cubic zirconia?

These are just two of the questions buyers often ask before buying wedding jewelry.

Obviously, these are different stones and questions are very well asked!

Here are the most important differences between diamond and cubic zirconia that will help you make the right decision.

What is cubic zirconia?

First, cubic zirconia is not a diamond.

It is a colorless diamond simulant made in the lab.

Although they can be found in nature, they are very rare.

Thus, most cubic zirconia jewels are man-made synthetic stones.

Cubic zirconia vs Diamond side by side comparison
Cubic Zirconia Diamond
Hardness 8.5 10
Density 5.5 to 5.9 3.5 to 3.53
Dispersion 0.058 to 0.066 0.044
Refractive Index 2.088 to 2.176 2.418
Flawless Constantly Rarity


Diamond is harder than Cubic zirconia

In the gem world, hardness is measured on the Mohs scale. Diamond has the top spot with a 10 grade. CZ comes behind it with a rating of 8.5.

Diamond is more durable than cubic zirconia

CZ stones get scratched more easily than diamonds. Moreover, you’ll have hard time finding a material to cause a scratch on your diamond ring. On the other hand, a bracelet with CZ stones may get scratched much more easily.

Cubic zirconia has no inclusions like diamond

During its formation, different materials may be enclosed in the crystal structure of diamonds. This may give it a yellowy, grayish tint or even change its color significantly.

On the other side, CZ is produced in a controlled environment. Thus it is almost flawless as it has nearly no inclusions in its formation.

Cubic zirconia has more clarity than diamond

Diamond may have a minority of other elements in its formation. These will decrease clarity of the gemstone. CZ is immune from these outsiders and offers a practically flawless jewel.

Cubic zirconia has nearly twice the density of diamond

CZ’s density is 5.5-5.9 g/cm3, fluctuating on its composition.

This approximately doubles that of diamond. Diamond’s density is around 3.5 g/cm3.

They are both measured in carats.

Carat is 0.2 grams or 200 milligrams.

Cubic zirconia is a better thermal insulant than diamond

Diamond has a higher heat conductivity. Its thermal

Diamond is much more expensive than cubic zirconia

As CZ is produced in the lab, its supply is easily expandable.

On the other hand, diamonds are formed naturally outside our reach. We are bounded by natural limits.

How to tell cubic zirconia from diamond?

You can use differences in heat, clarity and density to distinguish between these two stones.

    1. When you breathe on a diamond, it will quickly dissipate heat and return to its initial look.However, when you breath on a cubic zirconia stone, it will stay foggy, and it will take longer to fade away.Diamond’s high conductivity makes the difference.This is a simple way to tell a real diamond from a cz stone.In doubt, never refrain from asking to the seller or consulting a jeweler to identify between diamond and cubic zirconia jewelry.
    2. CZ is colorless and has no inclusions while diamond may have other elements in its crystal.When hold to light, cubic zirconia will disperse rays into all colors of the rainbow in a more identifiable way than diamond.
    3. If you have a jeweler’s scale at disposal, you may weight same volume stones and see which one is heavier.CZ will have near double the weight thanks to its high density.


If you liked this post, you may be interested in our black sapphire vs black diamond, cubic zirconia vs white sapphire and cubic zirconia vs white topaz posts too.