Cubic zirconia vs diamond: the difference, and what lab-grown means

What is cubic zirconia?

Cubic zirconia is a crystal of zirconium oxide, made in the lab. No mine involved. Well cut, it looks remarkably like a diamond: clear, colourless and full of sparkle.

It isn't a fake diamond. It's a stone in its own right, with its own name. And cubic zirconia isn't the same as zircon: that's a natural gemstone from the earth.

At TOV, cubic zirconia is always set in real gold. The stone comes from the lab; the ring, earring or necklace around it is real 14k or 18k gold, hallmarked 585 or 750.

Cubic zirconia, diamond and lab-grown side by side

In short: cubic zirconia looks like a diamond, a lab-grown diamond is one. Only the origin differs.

What do F-G and SI mean?

Diamonds are graded on the four Cs: colour, clarity, cut and carat. In plain English:

• Colour: F-G. The scale runs from D (completely colourless) to Z (light yellow). F and G sit near the top: near colourless. To the naked eye, you see no yellow.
• Clarity: SI. SI stands for slightly included: small natural inclusions, traces of how the diamond grew in the earth. You usually only see them under a loupe.
• Cut: brilliant. Most TOV diamonds are brilliant cut: round, with dozens of facets that bounce the light back.
• Weight: ct. The number before ct is the weight. On a piece with several small stones, it's usually the total of all of them together.

Every TOV diamond ring comes with a certificate. Everything about colour, clarity and cut is in our diamond guide.

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Pavé Diamond Huggie Hoops (12mm) (0.12 ct) £529.00 Diamond Alliance Ring (0.15 ct) £599.00 Diamond Graduated Ring (0.17 ct) £594.00

Can you see the difference?

To the naked eye, from a little distance: hardly anyone can. Up close, there are a few clues.

• The light. Cubic zirconia throws more rainbow flashes, a diamond more bright white light.
• The breath test. Breathe on the stone. On a diamond, the mist clears almost instantly; on cubic zirconia, it lingers for a few seconds.
• After years. Cubic zirconia can pick up fine scratches and sparkle a little less sharply. A diamond stays crisp.
• Want to be sure? A jeweller can test it in seconds with a diamond tester. Telling lab-grown from natural does take specialist equipment.

When to choose what

• Choose a natural diamond for a piece that's forever: an engagement ring, or a ring you'll never take off.
• Choose cubic zirconia for the look of a diamond, for pieces you like to switch up, or for a first stack with a cubic zirconia ring. The gold around it is every bit as real.
• Lab-grown is the same stone with a different origin. At TOV, you choose between natural diamond and cubic zirconia.

Freshen cubic zirconia with lukewarm water. On pieces with stones, polish only the gold.

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Pavé Cubic Zirconia Huggie Hoops (12mm) £279.00 Cubic Zirconia Trilogy Ring £299.00 Four Prong Round Cut Cubic Zirconia Ring £389.00

Gold Diamond Jewellery Natural diamonds, F-G colour and SI clarity, set in real gold. Shop Gold Diamond Jewellery