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Cubic Zirconia vs. Lab Diamond

While cubic zirconia (CZ) and lab diamonds may appear similar to the untrained eye, they differ significantly in composition, value, durability, and other characteristics.

Lab grown diamonds are real diamonds created in a laboratory environment using advanced technology that replicates the natural diamond formation process. They share the same physical, chemical, and optical properties as natural diamonds. Cubic zirconia, on the other hand, is a synthetic material made from zirconium dioxide. It is an entirely different gemstone, crafted to imitate the appearance of a diamond at a fraction of the cost.

*Please note that Brilliant Earth does not carry cubic zirconia.

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Expertise you can trust: All of our guides are meticulously researched and reviewed by our certified gemologists, content, editorial, and brand teams before publication to ensure industry-leading excellence and accuracy.

Difference Between Cubic Zirconia and Lab Grown Diamond

1. Durability

Lab grown diamonds are one of the hardest known materials and score a 10 on the Mohs scale of hardness. CZ is much softer, ranking 8-8.5 on the Mohs scale. 

2. Appearance

CZ has a higher dispersion rate than diamonds, giving it a rainbow-like sparkle. While this fire can be eye-catching, it may appear artificial to trained eyes. Lab grown diamonds exhibit a more natural brilliance and scintillation that’s indistinguishable from mined diamonds. 

3. Cost

Cubic zirconia is a cost-effective alternative, often priced at a fraction of the cost of lab grown diamonds. 

4. Longevity

Lab grown diamonds retain their brilliance and structure with proper care. CZ, while beautiful initially, may lose its luster over time and is much more susceptible to scratches and clouding. 

5. Weight

CZ is denser than diamonds, meaning a CZ of the same size will weigh more than a lab grown diamond.

Cubic Zirconia vs. Lab Grown Diamond

Cubic Zirconia vs. Lab Diamond FAQ

Are lab grown diamonds cubic zirconia?

No, lab grown diamonds are not cubic zirconia. While both are created in controlled environments, lab grown diamonds have the same chemical and physical properties as mined diamonds. CZ is a distinct synthetic material composed of zirconium dioxide and lacks the hardness, brilliance, and intrinsic value of diamonds.

Is cubic zirconia better than lab grown diamond?

Cubic zirconia may be better for budget-conscious shoppers seeking a temporary or low-cost alternative. However, lab grown diamonds offer superior durability, making them a better investment for long-term use.

How can you tell a lab diamond from CZ?

These are key indicators for telling a lab diamond from CZ: 

  • Hardness: Lab grown diamonds resist scratches more effectively than CZ. 
  • Brilliance: Diamonds exhibit more subtle brilliance, while CZ sparkles with a rainbow-like fire. 
  • Weight: CZ feels heavier than diamonds of the same size.

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

Most people cannot distinguish between CZ and diamonds with the naked eye, especially when the stones are well-cut. However, subtle differences, such as CZ’s exaggerated sparkle and slightly less sharp facets, can be obvious to a trained eye.

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