Cubic Zirconia Versus Diamonds: What's the Difference?

The introduction of cubic zirconia to the jewelry industry forever changed the way we think of and deal with diamonds. Referred to as a diamond imitation (or "simulant"), cubic zirconia ushered in a cost-effective option for those who wanted the sparkle of a diamond without the higher price point. 

Ultimately, it’s not quite as simple as that. Yes, cubic zirconia may be budget-friendly, but that's not the only factor that sets it apart from a diamond. Learning about the differences—and there are several—between these two types of stones will take you on an educational journey that spans history and science. Ahead, a complete guide to the differences between cubic zirconia and diamonds and why knowing these factors will be helpful when you’re choosing a piece of jewelry (namely, an engagement ring).

What Is a Diamond?

The first thing you should know about diamonds is that they’re old—really, really old. "Most natural diamonds are estimated to be between one billion and 3.5 billion years old," Ring Concierge founder and CEO Nicole Wegman tells Brides. "They were formed hundreds of miles beneath the earth’s surface." On a molecular level, a diamond is a gemstone that is composed of carbon atoms in a crystal lattice arrangement. Diamonds can form naturally or grow in a laboratory.

What Is Cubic Zirconia?

Cubic zirconia, on the other hand, was discovered as a natural mineral in 1937 and introduced as a synthetic to the market in the 1970s. "Cubic zirconia is made in a lab by melting zirconium dioxide with stabilizers. Once these chemicals harden into a rock form, they are cut and polished," Wegman explains.

Diamonds vs. Cubic Zirconia

Price

Unsurprisingly, because it is manmade and considered a diamond simulant, cubic zirconia is going to cost considerably less than a diamond. "Natural diamonds typically range anywhere from $7,000 to $10,000 per carat based on quality and exact specifications," Wegman says. "A cubic zirconia is typically less than $30 per 'carat.'"

Due to this vast price difference, it makes sense that cubic zirconia is the dominant diamond imitation, with current production of approximately 60 million carats per year, according to the Gemological Institute of America.

Durability

The durability of minerals is ranked on something called the Mohs Hardness Scale, with values between 1 and 10. "Diamonds are a 10 on the Mohs Hardness Scale, meaning they are the hardest gemstone," Wegman says. "A cubic zirconia is roughly an 8 to 8.5, meaning it will chip and scratch much easier than a diamond would."

If you’re someone who works with their hands often or simply tends to be less delicate with jewelry, a more durable gemstone is something worth prioritizing so it can be preserved longer.

Color

"A cubic zirconia is an imitation of a perfect diamond, so it will have the appearance of being colorless and flawless," Wegman says. In addition to colorless designs, cubic zirconia can be produced in almost any color, with GIA noting that convincing pink and yellow imitations exist in the market.

Natural diamonds are graded on a scale of D to Z, with D representing colorless diamonds. True colorless natural diamonds are extraordinarily rare and expensive, which is why you’re more likely to find a near-colorless diamond graded G through J.

Clarity

As Wegman mentioned above, cubic zirconia imitates a perfect diamond, meaning one without flaws. However, virtually all natural diamonds will have inclusions; meaning, slight imperfections or blemishes that are usually only visible with professional equipment.

Shopping Considerations

Though similar in appearance, spotting cubic zirconia with the naked eye is still possible. "Cubic zirconia overall will have a more glassy appearance where diamonds have more depth," Wegman explains. "A trick to tell the difference in person: If you place the stone over printed text on paper and you can read the words through the stone, it's not a diamond and is likely a cubic zirconia or other simulant."

Additionally, cubic zirconia lacks the brilliance and fire that a diamond has, meaning light passes through it differently than it would through a diamond. Cubic zirconia also has a higher dispersion rate, which is why it often gives off that rainbow effect that can make it look cheaper.