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Cubic Zirconia vs. Diamond: What’s the Difference?

Cubic Zirconia vs. Diamond What’s the Difference

Cubic zirconia and diamonds differ significantly in appearance, durability, and price. This guide offers a detailed comparison to help you understand the differences between the two stones. 

Cubic Zirconia

Cubic zirconia (CZ) is a man-made stone, developed in the 1970s as a cost-effective diamond simulant. It is composed of zirconium dioxide (ZrO?) and is created in a controlled lab environment. Cubic zirconia is known for its ability to mimic the look of a diamond while being available at a much lower cost. It is commonly used in costume or fashion jewelry and available in many cuts and colors. Cubic zirconia is not the same as natural diamonds or lab diamonds. 

Diamond

Diamonds are gemstones that form either under high pressure and temperature conditions deep within the Earth’s mantle or in controlled laboratory environments that mimic the natural process. They are composed of carbon atoms arranged in a crystal lattice. This unique composition gives diamonds their extraordinary hardness and light performance.  

Today, as they have been for centuries, diamonds are often used in fine jewelry and are one of the most beautiful, coveted objects on Earth. 

Cubic Zirconia vs. Diamond

Appearance

At a glance, cubic zirconia and diamonds can appear similar. However, upon closer look, their differences become apparent. Diamonds have a higher refractive index than cubic zirconia, which means they tend to sparkle more intensely. Diamonds also display a sharper brilliance and distinct fire. Cubic zirconia tends to show a rainbow-like effect, which can appear more artificial in certain lighting. 

Another difference is that CZ stones are perfectly transparent, whereas most diamonds have natural inclusions or slight color variations. For those looking for a stone that mimics the “perfect” appearance, CZ may be appealing—but this perfection can also make it easier to distinguish from a real diamond, which often has minor imperfections that give it character. 

Durability

One of the most significant differences between CZ and diamonds is their hardness. Diamonds are the hardest natural material on Earth, scoring a 10 on the Mohs hardness scale, which makes them highly resistant to scratching and damage. This durability makes diamonds ideal for daily wear in engagement rings and other fine jewelry. 

Cubic zirconia, by comparison, has a hardness of 8-8.5, meaning it is much more prone to scratching, chipping, and losing its luster over time. CZ is softer and more porous, so it can cloud or become dull with prolonged use, especially when exposed to chemicals or everyday wear and tear. 

Price

Price is one of the most significant differences between cubic zirconia and diamonds. Cubic zirconia often costs a fraction of the price of a diamond. A 1-carat CZ stone may cost a few dollars, whereas a 1-carat diamond can range in the thousands, depending on factors such as cut, clarity, color. 

Cubic Zirconia vs. Lab Diamond

Lab-grown diamonds are created using advanced technological processes that replicate the conditions under which natural diamonds form. Lab diamonds are chemically and physically identical to natural diamonds, and share the same hardness, brilliance, and fire. Learn more in our Lab Grown Diamond Guide.

In contrast, cubic zirconia is a different material altogether, made from zirconium dioxide. Cubic zirconia is not the same as diamonds or lab diamonds, while diamonds and lab diamonds are exactly the same except for their origin story. 

FAQ

Is cubic zirconia a diamond?

No, cubic zirconia is not a diamond. It is a lab-created material made from zirconium dioxide, designed to mimic the appearance of a diamond. 

Can the average person tell the difference between cubic zirconia and diamond?

For small stones or from a distance, cubic zirconia and diamonds can look alike. However, the differences in sparkle and appearance can be easily identifiable with a closer look. Diamonds display a sharper brilliance, distinct fire, more symmetrical cuts, and a higher polish. Cubic zirconia tends to show a rainbow-like effect, which can appear more artificial in certain lighting. Cubic zirconia is also transparent, whereas most diamonds, whether lab or natural, have inclusions or slight color variations. 

Does cubic zirconia pass a diamond tester?

No, cubic zirconia will not pass a diamond tester. Diamond testers measure thermal conductivity, and since diamonds have much higher thermal conductivity than cubic zirconia, the device will not register CZ as a diamond. 

Interested in learning more about diamonds? Check out our other Diamond Guides: Diamond Cut, Diamond Clarity, Diamond Carat, Diamond Color, Diamond Shape, Lab Grown Diamonds, Moissanite vs. Diamond, Moissanite vs. Lab Diamond, Cubic Zirconia vs. Lab Diamond, How Are Lab Grown Diamonds Made?, MM to Carat

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