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What is the difference between cubic zirconia and diamond

July 1, 2022

The introduction of cubic zirconia into the jewelry industry has forever changed the way we look at and handle diamonds. Known as diamond imitations (or “knock-offs”), cubic zirconia brings a cost-effective option to those who want the sparkle of a diamond without the high price tag.

But it’s not that simple. Cubic zirconia may be budget-friendly, yes, but understanding the differences between the two – and there are several – is a topic that spans history and science. Ahead is a complete guide to the differences between cubic zirconia and diamonds, and why it’s helpful to know these factors when you’re choosing jewelry, namely moissanite rings.

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 1 billion and 3.5 billion years old,” Nicole Wegman, founder and CEO of Ring Concierge, tells Brides. “They were formed hundreds of miles below the earth’s surface.” At the molecular level, diamonds are gemstones composed of lattice-arranged carbon atoms. Diamonds can form naturally or be grown in a laboratory.

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

Diamond and cubic zirconia
Not surprisingly, because cubic zirconia is man-made and considered a diamond imitation, it will cost significantly less than a diamond. “Depending on the quality and exact specifications, natural diamonds typically cost between $7,000 and $10,000 per carat,” says Wegman. “Cubic zirconia is typically less than $30 per ‘carat’.”

Because of this huge price difference, it makes sense that cubic zirconia is the leading diamond imitation, with current production of about 60 million carats per year, according to the Gemological Institute of America.

The durability of minerals is ranked on the Mohs scale of hardness, with values ranging from 1 to 10. “Diamonds are 10 on the Mohs hardness scale, which means they are the hardest stones,” Wegman says. “Cubic zirconia is about 8 to 8.5, which means it breaks and scratches more easily than diamonds.”

If you’re someone who works a lot with your hands, or just has less delicate jewelry, a more durable gemstone is something worth prioritizing so it can last longer.

“Cubic zirconia is a replica of a perfect diamond, so it has a colorless and flawless appearance,” says Wegman. In addition to its colorless design, cubic zirconia can be produced in virtually any color, and the GIA notes that convincing pink and yellow imitations exist on the market.

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

As Wegman mentioned above, cubic zirconia mimics a perfect diamond, i.e. a diamond without flaws. However, almost all natural diamonds will have inclusions; meaning minor flaws or imperfections that are usually only visible with specialized equipment.

Shopping Considerations
Although similar in appearance, cubic zirconia can still be spotted with the naked eye. “Cubic zirconia as a whole will have a more glassy appearance, while diamonds have more depth,” explains Wegman. “The trick to identifying the difference in person: if the stone is placed on printed text on paper and the text can be read through the stone, it is not a diamond and is most likely a cubic zirconia or other imitation.”

In addition, cubic zirconia lacks the brilliance and fire that diamonds have, which means that light passes through it differently than it does through a diamond. Cubic zirconia also has a high dispersion rate, which is why it often gives off a rainbow effect, making it appear cheaper.