Moissanite vs. Cubic Zirconia: What's the Real Difference? (And Why It Matters)

August 28, 2026

Moissanite and cubic zirconia (CZ) are both diamond alternatives — but they are fundamentally different materials with dramatically different performance over time. If you're comparing the two, here's what you need to know.

What They Are

Moissanite is silicon carbide (SiC) — a naturally occurring mineral first discovered in a meteorite crater by Henri Moissan in 1893. Modern moissanite is lab-created silicon carbide, produced in controlled conditions. It is a genuine gemstone with exceptional hardness, brilliance, and chemical stability.

Cubic zirconia (CZ) is zirconium dioxide (ZrO₂) — a synthetic material with no natural counterpart in gemstone form. It was developed in the 1970s as a diamond simulant and has been widely used in fashion jewelry since then.

Hardness and Durability: A Significant Difference

This is the most important practical difference between the two materials.

Moissanite: 9.25 on the Mohs hardness scale. Will not scratch from contact with everyday surfaces. Suitable for daily wear for decades.

Cubic zirconia: 8.0–8.5 on the Mohs hardness scale. Will scratch from contact with harder materials — including dust particles (which contain quartz, rated 7.0). A CZ stone worn daily will develop surface scratches within months to years, causing it to look dull and cloudy over time. This is not a cleaning issue — it's permanent surface damage.

This single difference is why moissanite is fine jewelry and CZ is fashion jewelry. A moissanite ring purchased today will look identical in 30 years. A CZ ring worn daily will look noticeably degraded within 2–5 years.

Brilliance and Fire

Moissanite: Refractive index 2.65–2.69, dispersion 0.104. Produces more brilliance and fire than diamond. Exceptional optical performance.

Cubic zirconia: Refractive index 2.15–2.18, dispersion 0.060. Produces good brilliance when new, but significantly less than moissanite. As the surface scratches with wear, brilliance decreases further.

A new CZ can look impressive. A worn CZ looks dull. A moissanite looks the same after 20 years as it did on day one.

Price

Moissanite: $300–$600 for a 1-carat DEF/VVS1 stone. A meaningful investment in a piece of fine jewelry.

Cubic zirconia: $5–50 for a 1-carat stone. Inexpensive fashion jewelry.

The price difference reflects the quality difference. Moissanite is not expensive CZ — it is a fundamentally different material with fundamentally different performance.

The Bottom Line

If you want a ring you'll wear every day for years and want it to look beautiful throughout — moissanite. If you want an inexpensive piece for occasional wear or a specific event — CZ is a reasonable choice for that purpose.

For an engagement ring or any ring intended for daily wear, CZ is not a suitable material. Moissanite is. Read our original comparison: Moissanite vs. CZ: Why One Lasts Forever and the Other Fades.

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