Soon after i t was first marketed in 1976, colorless cubic zirconia became the dominant diamond imitation, with current production of approximately 60 million carats per year. Although cubic zirconia was discovered as a natural mineral in 1937, crystals usable for faceting were first produced ill 1969 and it was not until a practical sltull-melting technique was developed in the USSR in 1972 that commercial production became feasible. This article reviews the sl