Cubic Zirconia (CZ) Explained: The "American Diamond" Guide

Cubic zirconia, usually shortened to CZ, is the most popular diamond simulant in fashion jewellery. In India it is often called "American diamond" or "AD". CZ offers impressive brilliance at a fraction of the price of diamonds, which makes it a favourite for engagement-style rings, bridal sets, earrings and evening jewellery. This guide explains what CZ is and how to choose and care for it.

What is cubic zirconia?

Cubic zirconia is a lab-created crystal made from zirconium dioxide, stabilised in a cubic crystal structure. It is manufactured in large quantities and can be produced colourless or in many colours. CZ became widely available in jewellery in the 1970s and quickly became one of the most common diamond simulants.

Important distinction: CZ is a simulant: it imitates the look of diamond but is a different material. It is not a lab-grown diamond. Lab-grown diamonds have the same chemical composition and crystal structure as natural diamonds; CZ does not.

CZ vs diamond vs glass

CZ often shows more rainbow "fire" than diamond, which experienced eyes may notice. For gemmological detail, see the GIA Gem Encyclopedia.

What makes good CZ jewellery?

Cut quality

Well-cut CZ has precise, symmetrical facets that return light brightly. Poorly cut stones look dull or "glassy".

Clarity and colour

CZ is usually free of visible inclusions. Colourless CZ should look clear and white rather than grey or cloudy.

Setting quality

• Prong settings show off the most sparkle but can catch on fabric.
• Bezel settings protect stones with a metal rim.
• Pavé and micro-pavé use many tiny stones closely set together; check that none are missing or loose.
• Channel settings hold stones between metal walls.

See Stone Setting Techniques.

Plating

CZ jewellery is often rhodium-plated for a bright white look, or gold- or rose-gold-plated. Check for even plating, especially around settings.

Why CZ can lose sparkle

CZ itself does not "fade", but jewellery can look dull because of:

• Film from skin oils, lotion and soap on the back of the stone, which blocks light
• Scratches and abrasions over time, as CZ is softer than diamond
• Worn plating around settings

How to keep CZ sparkling

1. Wipe stones gently with a soft, lint-free cloth after wearing.
2. For plain, well-set CZ without glue or delicate plating, a soft brush with a little mild soapy water, followed by thorough drying, can remove film. Do not soak, and avoid this method entirely for glued stones or plated pieces where water may cause damage.
3. Avoid ultrasonic cleaners for fashion jewellery; vibrations can loosen stones and damage plating.
4. Store separately so CZ does not scratch other pieces, and harder materials do not scratch CZ.
5. Remove before applying creams and before washing hands.

See How to Clean Imitation Jewellery Safely.

Buying honest CZ

• Look for clear labelling such as "cubic zirconia", "CZ" or "American diamond (CZ)".
• Be cautious of descriptions that suggest real or lab-grown diamond without certification.
• Check whether the base is brass, silver or steel, and what plating is used.

Styling CZ jewellery

• Evening and receptions: CZ necklace sets, drop earrings and cocktail rings.
• Bridal and engagement: CZ rings and sets with pastel or ivory outfits.
• Everyday: small CZ studs and pendants add sparkle without effort.
• Office: modest CZ studs or a fine tennis bracelet.

Key takeaway

Cubic zirconia offers diamond-like brilliance at an accessible price. Choose well-cut, securely set stones with good plating, keep them free of film, and store them carefully for lasting sparkle.

Sources and further reading

• GIA Gem Encyclopedia
• U.S. eCFR — 16 CFR Part 23, FTC Guides for the Jewelry, Precious Metals, and Pewter Industries

Written by

HANSINI369 Editorial Team

Our editors research jewellery types, materials, care and craft, and review guides when materials, standards or recommendations change. Read our editorial policy.