Cubic Zirconia, Moissanite, Diamond: What's the difference and what to choose
Diamond, moissanite, and cubic zirconia are not the same thing. And it's not simply "expensive, medium, cheap." They have different chemistries, different brilliance, and different behavior over time. Here's what truly distinguishes them from one another.
Cubic Zirconia (CZ)
Zirconium dioxide. Made in a laboratory specifically to imitate diamond — that's precisely what it was invented for. Hardness of 8-8.5 on the Mohs scale, meaning it can be scratched by contact with harder materials like keys, sand, or other stones.
The main problem is that it clouds. Not from scratches, but chemically: its surface gradually becomes dull and cleaning won't restore its brilliance. After 1-3 years of intensive wear, CZ noticeably ages.
Price — the lowest. It is widely used in mass jewelry production. If a jewelry description says "crystal" or "stone" without further clarification, it's most likely cubic zirconia.
Moissanite
Silicon carbide. Natural moissanite is a very rare mineral found in meteorites. Gem-quality moissanite is grown in a laboratory. It's not a diamond imitation — it's a distinct material with its own characteristics.
Hardness of 9.25 — after diamond, it's the second hardest material in jewelry. It can only be scratched by a diamond or another moissanite.
Refractive index of 2.65 — higher than that of diamond (2.42). This means it sparkles more intensely in light. Some prefer it, some less so — it's a matter of taste. But it will never dull.
Price — 10-15 times lower than a diamond of similar size. That's why rings and necklaces with moissanite allow you to get a large stone without the corresponding price tag.
Diamond
Natural carbon. Hardness of 10 — the hardest natural mineral. Refractive index of 2.42 — slightly lower than moissanite, but the brilliance is very high quality and distinctive.
Every natural diamond is unique — a geological event from billions of years ago. This is the main argument for those who choose natural stones: not just physical characteristics, but their origin.
There are also lab-grown diamonds — chemically identical to natural ones, cheaper, but lacking that "uniqueness." The market for them is currently controversial.
Comparison
Hardness: diamond 10, moissanite 9.25, cubic zirconia 8-8.5. For everyday wear, the critical difference is between CZ and the rest — it scratches from everyday contact.
Brilliance over time: diamond and moissanite do not dull. Cubic zirconia dulls after 1-3 years.
Price per 1 carat: natural diamond from $4,000, moissanite $400-700, cubic zirconia $5-20.
What to Choose
Cubic zirconia — if the jewelry is not for daily wear and price is critical. Or if you're buying for a child and know it will be discarded in a year.
Moissanite — if you want an everyday stone that's large, has strong brilliance, and doesn't require you to worry about being careful. And if natural origin is not a principle concern.
Diamond — if the natural, unique aspect is important, or if it's a gift with specific meaning where price is secondary.
Frequently Asked Questions
Can a jeweler distinguish moissanite from diamond?
With a standard tester — no, most testers give a positive result for both. A special moissanite tester is needed. To the naked eye without instruments — practically impossible for an untrained person.
Is cubic zirconia the same as "rock crystal"?
No. Rock crystal is natural transparent quartz. Cubic zirconia is zirconium dioxide. They are different materials with different properties, although both are transparent.
Are there certificates for moissanite?
Yes. A reputable seller provides a gemological certificate for the stone. In SIERRA SPACE, moissanite in the Alma collection comes with a stone certificate.
