Lab-grown diamond, moissanite and cubic zirconia (CZ) are often compared because all three can look like a diamond at first glance. But they are three different materials, and they behave very differently over years of wear.

What they are

  • Lab-grown diamond: pure carbon in a diamond crystal, chemically and physically a diamond.
  • Moissanite: silicon carbide, a different gemstone that is almost always lab-made for jewellery.
  • Cubic zirconia: zirconium dioxide, an inexpensive synthetic diamond simulant.

Hardness and durability

  • Lab-grown diamond: 10 on the Mohs scale, the hardest natural material.
  • Moissanite: 9.25, very hard and durable.
  • Cubic zirconia: 8–8.5, which scratches and clouds over time with daily wear.

For an engagement ring worn every day for decades, hardness matters.

Sparkle

  • Diamond shows a balance of white brilliance and coloured fire.
  • Moissanite has more fire, which can look like "rainbow" flashes, especially in larger stones. Some people love it; others find it less diamond-like.
  • CZ sparkles well when new but loses its lustre as the surface scratches and collects grime.

Colour

Lab-grown diamonds are graded on the standard D–Z colour scale. Moissanite can show a faint grey or yellow tint in some lighting. CZ is colourless when new.

Price

CZ is the least expensive, moissanite sits in the middle, and lab-grown diamonds cost more than moissanite but far less than mined diamonds of the same size and quality.

Which should you choose?

  • Choose a lab-grown diamond if you want a real diamond with diamond sparkle and hardness, for an engagement ring or heirloom piece.
  • Choose moissanite if you love extra fire and want the lowest price for a durable, larger-looking stone.
  • Choose CZ for fashion jewellery or travel pieces where cost matters more than longevity.

The label test

Whatever you buy, the seller must describe it accurately. A lab-grown diamond comes with a grading report stating laboratory-grown diamond; moissanite and CZ are not diamonds and shouldn't be sold as such.

Want to see the difference? Contact us for certified lab-grown stones.