Cubic Zirconia (CZ) is a lab-created crystal made from zirconium dioxide (ZrO₂), stabilized with small amounts of yttrium or calcium oxide so it holds a cubic crystal structure. It is grown by melting high-purity powders at over 2,700 °C in a process called skull melting, then cooling them into clear, flawless crystals. First produced commercially in the 1970s, CZ has become the most popular diamond alternative thanks to its exceptional brilliance, strong fire, good hardness, and accessible price. It is not the same as natural zircon, which is a different mineral.
- Color Range: Most often colorless; also made in pink, champagne, yellow, orange, red, green, blue, purple, and black by adding trace elements during growth
- Sizes: Widely available from tiny 1 mm accent stones to 15 mm and larger center stones
- Shapes: Round brilliant, princess, oval, pear, marquise, cushion, emerald, heart, and baguette cuts; occasionally cabochons
- Origin: Lab-created; not mined
- Hardness: 8 to 8.5 on Mohs scale
- Luster: Sub-adamantine, a bright, near-diamond luster
- Fire & Brilliance: Refractive index of about 2.15–2.18 and dispersion of about 0.060, giving more rainbow fire than diamond
- Transparency: Transparent and typically free of visible inclusions
- Distinctive Characteristics: About 1.7 times heavier than a diamond of the same size, with a flawless clarity and lively colored flashes
- Care: Clean with warm soapy water and a soft brush; lotions and oils can dull its sparkle, so wipe stones regularly
