Cubic Zirconia (CZ)
A synthetic crystalline material (ZrO₂) used as an affordable diamond simulant, available in grades from A to AAAAA.
Last updated: July 6, 2026
Detailed Explanation
Cubic Zirconia (CZ) is a synthetically produced crystalline form of zirconium dioxide (ZrO₂). First synthesized in 1937 and commercially produced for jewelry since 1976, CZ is the most widely used diamond simulant due to its high refractive index (2.15-2.18), strong dispersion (0.058-0.066), and good hardness (8-8.5 on Mohs scale). CZ is graded from A (lowest) to AAAAA (highest) based on cut precision, clarity, and color consistency. AAAAA-grade CZ is machine-cut to precise proportions and is visually difficult to distinguish from diamond without gemological instruments. CZ is heavier than diamond (5.6-6.0 g/cm³ vs 3.5 g/cm³).
Common Uses
Stone-set rings, earrings, pendants, bracelets — any design where diamond-like appearance is desired at lower cost.
Advantages
Excellent brilliance and fire, very low cost compared to diamond, available in many colors, consistent quality.
Limitations
Softer than diamond (can scratch over time), heavier than diamond, can appear "too perfect" compared to natural stones.