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Lab Created Diamond vs. Cubic Zirconia (CZ)

Man holding lab created diamond engagement ring in a red box

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 There’s a misconception that lab created diamonds and cubic zirconia (often simply called CZ) are the same thing – inexpensive diamond simulants. This is not true and there is a world of difference between these two types of stones.

Let’s take a closer look at the difference between lab created diamonds and cubic zirconia and why they are not the same thing.

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Origin and Composition

Round shape diamond

See more lab created diamonds HERE.

A lab created diamond may have been created in a lab using science and technology, but it is still an authentic, genuine diamond. Lab diamonds are made of the same substances are earth mined diamonds – carbon atoms arranged in a specific cubic crystal structure, characteristic of natural diamonds. They are ‘real’ diamonds with no difference in appearance or other characteristics.

Loose round cubic zirconia

Loose cubic zirconia stone. See more HERE.

Cubic zirconia, on the other hand, simply looks like a diamond but has no similarities with diamonds apart from appearance. Cubic zirconia is also lab created but contains no carbon. Instead it’s the cubic crystalline form of zirconium oxide. CZ is known for being inexpensive and simply a diamond look alike.


Lab grown diamonds have the exact same characteristics as mined diamonds. In general, diamonds have better sparkle than CZ and interact with light in a different way. Some characteristics of lab grown diamonds include:

  • A hardness ranking of 10 on the Mohs scale
  • A high refractive index of 2.42
  • Dispersion (diamond fire) of 0.044
  • Color grades ranging from D to Z (colorless to yellow)
  • Clarity grades ranging from IF to I1.
  • Cost of upwards of $2500 per carat

Cubic zirconia, on the other hand, has different characteristics. It has higher dispersion, which can result in heightened fire or colorful flashes that’s visible when the stone is under light. CZ also tends to be flawless clarity and color wise. Here are some characteristics of CZ:

  • A hardness ranking of 8 to 85 on the Mohs scale
  • A refractive index of 2.2
  • Dispersion (fire) of 0.066
  • Color typically always D grade, but may show some tints of yellow or green under UV lighting
  • Clarity typically always IF
  • Cost of upwards of $20 per carat


There’s no arguing with the fact that diamonds are among the most durable of all materials used in jewelry. They have excellent scratch resistance, being the hardest material used in jewelry, and good toughness. Diamonds are also easy to maintain and keep clean and will always retain their sparkle.

Cubic zirconia also has very good hardness, at 8 on the Mohs scale, which is equivalent to the Beryl group of minerals – aquamarine, emerald, morganite and heliodor all have a rating of 8. However, this means that CZ is more prone to scratches and can sometimes become cloudy over time. It requires more maintenance to keep it sparkling.

In Engagement Rings

Girl wearing cubic zirconia engagement ring

Lab grown diamonds are an excellent choice for engagement rings, because you get the durability and beauty of a diamond at a much lower price. Note, however, that lab diamonds aren’t exactly cheap – they’re only relatively inexpensive in comparison to mined diamonds.

Cubic zirconia is a great alternative if you’re on a budget or you just don’t buy into the diamond engagement ring scenario. CZ is much cheaper than diamonds, and you can get yourself an amazing CZ ring for a fraction of what it would cost you to get a diamond ring. Note that there are durability issues to consider, but even so, replacing a CZ down the track is still a relatively inexpensive option.

James Allen lab created diamond filter

See a Wide Range of Lab-Created Diamonds Here

You will find lab grown diamonds offered on reputable retail stores like James Allen and even on sites like De Beers (which is often credited for being responsible for the mined diamond engagement ring industry). However, cubic zirconia is not sold on these top engagement ring retail stores, as there’s the concern that this can downgrade the quality of their products in general.

cz engagement ring closeup

CZ engagement ring by Pescara Jewelry. See it HERE.

If you’re looking for a high-quality CZ engagement ring, we suggest searching on Etsy where there’s a range of beautiful CZ ring designs. You can also find a designer who will be willing to custom create a ring for you.

Which is Better?

If you don’t have budget restrictions, a lab created diamond offers you more long term value and is an heirloom stone. You can always pass down your lab-created jewelry to future generations, because it is, after all, a real diamond.

Cubic zirconia, on the other hand, has no inherent value and its only value lies in being a budget-friendly diamond look-alike. Still, there’s a lot to be said for CZ engagement rings and according to this article, only smart people buy them. Whatever your feelings are on this, when choosing between cubic zirconia and lab created diamonds, consider why you’re buying this stone, what you want it to say about you and how you want to feel about the stone. By examining your values and what matters to you, you’ll be able to choose between a mined diamond, lab diamond and a CZ stone.

What Do People Say?

While opinion is divided on whether to opt for these stones, here’s what some brides think about CZ and lab grown diamond engagement rings.

Jennifer: I’ve seen gorgeous CZ rings. I think what matters is that you love it and not give a hoot about what others may say about your ring.

Pan: My ring has a cubic zirconia and it really doesn’t matter to me. I’m not a diamond person and I can’t justify spending thousands on a piece of rock.

Stella: I would opt for lab grown diamonds because I’ve heard lots of stories that it’s hard to resell diamonds for the value you would be satisfied with anyway. I’d rather get a lot of use out of my stone and not concern myself with the resale value.

Maryam: My fiancé got me a lab created diamond engagement ring but that’s the only kind I wanted. I know it’s conflict free and hasn’t cost the earth, literally.

So what do you think? Would you choose a CZ or a lab grown diamond?