How does cubic zirconia differ from a lab-grown diamond in silver?

925 sterling silver jewellery, set with lab grown diamonds and made in our own Shenzhen workshop.

Posted on October 25, 2026by test111

Talk · Lab-Grown Diamond Knowledge

QThe questionEditorial scenario written by the ZKZ team. Not a customer post.

A buyer sees two silver rings that look alike, one set with cubic zirconia and one with a lab-grown diamond, at very different prices. They ask what actually separates the stones and which suits daily wear.

ZKZ Editorial TeamMain answer · Product & gemmology desk

Cubic zirconia (CZ) is a different material from a diamond. A lab-grown diamond is a diamond that was made in a lab, with the same basic composition and structure as a mined one. CZ is a simulant that only resembles it.

The materials

Fact The FTC Jewelry Guides define a diamond as a mineral of essentially pure carbon crystallised in the isometric system, with a hardness of 10, a specific gravity of about 3.52 and a refractive index of 2.42 (16 CFR 23.12).

Fact The Guides also say a laboratory-grown stone may be called by the gem name only with a clear qualifier such as "laboratory-grown", and that an imitation should be identified as imitation or simulated (16 CFR 23.25).

Our advice In plain terms, a lab-grown diamond is a diamond. CZ is zirconium oxide, so it should never be sold as "diamond" without clear labelling as an imitation.

What this means for you

Look: a lab-grown diamond and CZ can look alike at a glance. Trained eyes and simple tools can tell them apart.
Durability: the Guides give diamond a hardness of 10. We generally find CZ scratches and dulls sooner, though we do not cite a figure here.
Care: both can be cleaned with warm soapy water and a soft brush. Keep both out of harsh chemicals.
Price: the difference reflects the material, and often the grading documents that come with a lab-grown stone.

How to tell what you are buying

Read the listing for the words "laboratory-grown diamond" or "cubic zirconia".
Look for a report number from an independent laboratory for the diamond.
Ask what the stone is if the listing only says "stone" or "gem".

Which suits daily wear

It depends If you wear the ring every day and want a diamond, choose the lab-grown diamond. If you want a lower-cost fashion piece and are happy to replace it, CZ can be reasonable. It depends on budget and how long you expect to keep it.

Uncertain We cannot compare exact scratch resistance here with a cited number, so treat our durability remark as experience, not a test result.

Sources

Fact = stated by the cited source. Our advice = editorial recommendation. Uncertain / it depends = limits of what can be said in general.

Other perspectives from the ZKZ team

SEZKZ Editorial TeamSelection perspective

Decide first whether you want a diamond or a look-alike. If you want a diamond, ask for the report number and check it with the laboratory.

COZKZ Editorial TeamDisclosure & compliance perspective

Words such as "diamond-like", "faux diamond" or "simulated diamond" need care. The FTC Guides say "faux" is not an adequate disclosure on its own, so the listing should state plainly what the stone is.

CSZKZ Editorial TeamCare & maintenance perspective

Both stones can clog with oils and soap, which dulls the sparkle. A gentle clean every few weeks restores more shine than most buyers expect.

Have a different question? Ask our team, or browse more answers in Talk.

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