Moissanite and cubic zirconia get lumped together often, but they're not the same thing. Both are diamond alternatives, and both look bright and clear from a distance. Once you know what to look for, the difference is obvious, and it matters for how long the stone stays looking good.
If you haven't read our full breakdown of what moissanite actually is, start with our moissanite guide before comparing it to CZ.
What They're Made Of
Moissanite is silicon carbide, a mineral that occurs naturally in trace amounts but is lab-created for jewellery. Cubic zirconia is a synthetic material, zirconium dioxide, made entirely in a lab and manufactured specifically to imitate diamond at low cost.
Hardness And Durability
This is the biggest practical difference. Moissanite rates 9.25 on the Mohs hardness scale, just below diamond's 10. Cubic zirconia rates around 8 to 8.5. In daily wear, that gap adds up. A CZ stone scratches and dulls faster, especially in a ring worn every day, while moissanite holds its edge and its shine for decades.
Sparkle And Fire
Moissanite actually has more fire, meaning more rainbow flashes of colour, than a mined diamond. Cubic zirconia has a duller, more glassy sparkle by comparison, and the difference becomes obvious under direct light once you've seen both side by side.
How Long They Last
A well-set moissanite stone can last a lifetime with normal care, the same as a diamond. Cubic zirconia is not built for the long term. It clouds, scratches, and loses its brilliance faster, which is why it's more commonly used in costume or fashion jewellery than in a ring meant to be worn every day for decades.
Price Difference
Cubic zirconia is cheaper than moissanite, but the gap in price reflects the gap in durability. For an engagement ring specifically, worn daily for years, moissanite is the better long-term choice even though it costs more upfront than CZ.
Certification
Moissanite from a reputable seller ships with documentation confirming what you're buying. Cubic zirconia typically doesn't carry the same certification, since it's sold as a budget alternative rather than a genuine gemstone. Read our 4Cs for moissanite guide to understand what to look for when you're shopping.
Every moissanite stone at MER SA ships certified, backed by a South African warranty, with free shipping and free resizing.
