Lab-Grown Diamonds Versus Cubic Zirconia: What’s the Difference?

Do you adore the sparkle, luster, and overall look of diamond jewelry, but want to avoid spending the cold, hard cash required to fully bling out? If yes, there are two affordable options you can consider when shopping for your wedding: cubic zirconia and lab-grown stones.

A lab-grown diamond is exactly what its name suggests; it's a diamond grown in a lab. What differentiates lab-grown stones from their mined counterparts, however, is that they're environmentally friendly and tend to be less expensive. "They will continue to exponentially increase in popularity because the quality of lab diamonds, when purchased from the right designer or brand, has become indistinguishable from their mined counterparts," explains jewelry designer Jean Dousset.

As for cubic zirconia (CZ), this affordable stone was once a staple for Millennial youth (remember those earring carousels at Claire’s?), and has since evolved into beautiful pieces that, to the untrained eye, can be tough to differentiate from real diamonds. "I love that people can feel good regardless of how much they spent [on cubic zirconia jewelry]," says jewelry designer Idunnu Tomori. That being said, CZs are synthetic stones and do not have the same chemical makeup as diamonds.

With all this in mind, we know it can be difficult to assess which affordable stone is the right one for you. So to help make your jewelry shopping process a little easier, we put together a guide that highlights the differences between lab-grown pieces and cubic zirconia. Read on to uncover how they vary in the most important ways, including cost, durability, and sparkle.

The Differences Between Lab-Grown Diamonds and Cubic Zirconia

Though they may look similar to the naked eye, lab-grown diamonds and cubic zirconia vary in many ways, as highlighted below.

Composition

Today, the most common process for creating a lab-grown diamond is called chemical vapor deposition, which places a small, slim slice of an already existing diamond (which can either be natural or lab-grown) in a vacuum. The vacuum then mimics the intense pressure and heat needed to create a naturally occurring diamond, which then results in a stone—made of pure carbon—that's almost identical to its natural look-alike

In contrast, cubic zirconia is the crystalline form of zirconium dioxide. Though a version of CZ can technically appear in a naturally formed stone, it is extremely rare, and all CZs on the market today are manmade. CZs are colorless and look like diamonds to the untrained eye, but they do not have the same chemical makeup as diamonds. (Again, diamonds are carbon and CZs are zirconium dioxide.)  For that reason, they are sometimes called "synthetic" or "simulated" stones when referenced in overlapping spheres.

Price 

Since lab-grown diamonds are not finite in amount, not subject to the same supply chains, and take less labor and energy to produce than traditional mining, they often cost considerably less—sometimes up to 50 percent less—than naturally occurring diamonds of a similar grade. "They put the consumers in charge and allow buyers to splurge on brands, designs, and diamond sizes and quality that they want," says Dousset. "The beauty of lab diamonds is that they allow people to have their desire met while lessening the emotional and financial burden that purchasing a diamond used to represent."

Cubic zirconia stones are even less costly to produce, primarily because they don’t require recreating pre-volcanic conditions that only exist far beneath the Earth’s crust. As such, they often go for a small fraction of what diamonds of similar size and cut would fetch, and the price disparity only increases as the stones increase in size. Per Tomori, a one- or two-carat CZ ring will almost never run you over $100.

Durability 

Like natural diamonds, lab-grown stones are the hardest substance on earth—a 10 on the Mohs hardness scale—and, thus, are extremely durable. You can knock one around and wear it through physically demanding activities (though not recommended), and there’s very little chance that the stone will fracture unless there's already a preexisting inclusion near the surface.

While CZs are also hard—typically an 8 to 8.5 on the Mohs scale—they aren't as durable as lab-created pieces. They can typically withstand the typical wear and tear of everyday life just fine, but, per Tomori, "you might see some scratches from knocking your hand around."

Clarity

Lab-grown diamonds are judged on the same scale as their natural counterparts—Flawless (F1) to Included (I3). Cubic zirconia stones, however, are rated on an overall quality scale of A (1A) to AAAAA (5A), with AAAAA being the highest quality. These ratings are most frequently referenced during wholesale purchases of CZs and are not likely to be displayed in the typical consumer purchase. Per Tomori, the sweet spot for quality and price is AAA, and that’s the one you’ll most often find on the market from reputable sellers.

Carat 

Cubic zirconia is slightly denser than a diamond, which makes it a heavier piece. What's more, cubic zirconia and a lab-grown diamond of the same carat weight will not be the same physical size, with the CZ being slightly smaller than the diamond.

Color 

Whether they’re mined or lab-grown, completely colorless (grade D) diamonds are extremely rare—and extremely expensive. Most couples instead look for diamonds that are near-colorless, or graded G through J (any yellow tint that the diamond may take on would not be noticeable to the naked, untrained eye).

CZs, on the other hand, are entirely colorless. They won’t feature any hue unless it’s intentional.