Cubic Zirconia vs. Diamond: Can you tell the difference?

Zirconia vs. Diamond: The Honest Comparison

Zirconia vs. Diamond – this question is as old as the artificial gemstone itself. Since the 1970s, zirconia (cubic zirconia, CZ) has been the most well-known diamond imitation. But how easy is it really to spot the difference?

What is Zirconia?

Cubic zirconia (CZ) is a synthetically produced metal oxide – not a mineral, not a real gemstone. It is industrially produced and can be visually very diamond-like.

Can you see the difference?

To the naked eye: With small stones (under 0.5 carats) – difficult. With larger stones – experts recognize it by:

• Fire (color dispersion): Zirconia shows more rainbow colors than diamond – "too colorful"
• Brilliance: Zirconia is often "too perfect" – no diamond is so flawless
• Weight: Zirconia is 60% heavier than diamond of the same size
• Scratches: Zirconia (Mohs 8.5) scratches faster than diamond (Mohs 10)

What Experts Use

• Thermometer test: Diamond conducts heat quickly, zirconia does not
• Thermal conductivity device: 100% reliable

When Zirconia is OK

• As fashion jewelry without a claim to value
• As a temporary placeholder (e.g., when traveling instead of a real engagement ring)
• In children's earrings

When Zirconia is Problematic

If zirconia is sold as a diamond – that is fraud. Only buy diamond jewelry with a GIA/IGI certificate.

At corelunejewellery.de, there are only real gemstones with transparent labeling – no zirconia sold as diamond.