Lab-Grown Diamonds vs. Cubic Zirconia

If you’ve landed on this page, there’s a really good chance that you’re trying to figure out the difference between lab-grown diamonds and CZs for a few reasons. 1) You’re trying to prove your significant other wrong by proving that they are in fact very different. 2) You’re trying to decide which would be a good option for your engagement ring. 3) You have a general idea of what each is, but you’re interested in learning more. No worries, all three scenarios (and more) will be addressed in the guide below. You’ll leave this page armed with all the knowledge you need to say, “told you so”.

Lab-Created Diamonds

First and foremost, lab-grown diamonds are exactly what their name implies-they are real diamonds. These diamonds may be created in a lab by human technology, but the technique is simply an accelerated process of the one that happened inside the earth over billions of years. Lab-grown diamonds are 100% identical, both chemically and structurally, to earth-grown diamonds, but, without the associated problems of extracting them through mining. They are both composed of carbon atoms formed into diamond cubic structures. Lab-grown diamonds are graded (by cut, color, clarity and carat) in the same way as earth-formed diamonds. Besides the ethical problems associated with diamond mining, the differences between the two are their origin and their cost. Mined diamonds have to be extracted by various means from above and well below the earth’s surface, while lab-grown diamonds are created in controlled environments. The price for mined diamonds can be up to 40% more expensive than lab-grown. So, buying lab-grown diamonds is both more affordable and socially-conscious than purchasing mined diamonds.

Cubic Zirconia

Cubic zirconia is not a diamond, but is instead a diamond simulant: a human-made gem meant to simulate, or look like a diamond. It may resemble a diamond in appearance, but it is not a precious stone and is not meant to be a replacement for a real diamond in fine jewelry. It is not chemically like a diamond at all. There is 0% carbon in cubic zirconia, unlike both earth and lab-grown diamonds, which are both composed of 100% carbon. Cubic zirconia is made of zirconium dioxide formed into a cubic crystalline structure. And, because cubic zirconia is not made of carbon, it is not as durable as a diamond. It has a hardness of 8 on the MOHS scale (a scale used to measure the relative hardness of a mineral, determined by its resistance to scratching), vs. a 10 on the MOHS for a diamond. Because of its increased hardness, a diamond’s edges are stronger and remain sharp when cut, while a cubic zirconia’s edges are more likely to dull and round off during the cutting process.

Price Difference

So, what does all of this mean for comparative costs between a lab-grown diamond and a cubic zirconia? Quite a bit, as one might imagine! Cubic zirconia averages right around $20 per carat, respectively. With such a vast difference in price, why and when would it make sense to purchase a lab-grown diamond instead of a cubic zirconia stone, and vice versa? Well, it turns out that there are reasons for both.

Reasons to Buy

Jewelry made from cubic zirconia certainly has its place. Because it is so affordable, it makes great costume jewelry. If you are a person who likes to change out your clothing and jewelry frequently, buying inexpensive rings, bracelets and necklaces made with cubic zirconia will allow you to do so! Cubic zirconia jewelry can also act as a great “place holder” for more expensive gems. If you cannot afford to buy a beautiful real diamond now, but still want to buy that engagement ring, for example, you can make the real (hopefully lab-grown) diamond a promise for the future when you can afford it.


Some people like to have two copies of their diamond jewelry, one for wearing at home and one for travel. They will have one piece made with their real diamonds and one made with cubic zirconia.This allows them to still wear a replica of their lovely necklace and matching earrings on their trip, but not have to fear losing them in a hotel room or being robbed halfway around the world. Some pregnant women have a copy of their diamond ring made with cubic zirconia at the beginning of their pregnancy, but with a larger band size. This allows their fingers to swell (yes, unfortunately, it happens!) without needing to re-size their ring a couple of times, or not wearing it at all. 

Simulated diamonds can be a nice alternative, but for many people the real thing is just worth it! Regardless of the possibility of using cubic zirconia as a stand-in for an engagement ring, most proposals are not done with an inexpensive ring, but instead, the ring’s value reflects the high value of the relationship. If you want to gift a loved one or yourself with jewelry whose brilliance, strength, and beauty is unmatched, then a diamond is the way to go. And, if you are like many folks today who are concerned with our environment and the ethical treatment of workers around the world, then buying lab-grown diamonds is your best bet!