Cubic zirconia (CZ) is a synthetic gemstone made from zirconium dioxide (ZrO2) in its cubic crystalline form. It is typically colorless but can be produced in a variety of colors. CZ was first developed in the 1970s and is widely used as a diamond simulant due to its close visual resemblance to diamonds, but it is much less expensive

. Key characteristics of cubic zirconia include:

• Hardness of about 8 to 8.5 on the Mohs scale (diamond rates 10), making it durable but less hard than diamond

• Specific gravity approximately 1.7 times that of diamond, meaning it is denser and heavier

• Refractive index of 2.15–2.18, slightly lower than diamond's 2.42, affecting its brilliance and sparkle

• High dispersion (fire) of 0.058–0.066, exceeding diamond's 0.044, which can give CZ a colorful sparkle

• Thermal insulating properties, unlike diamond which is a good thermal conductor

Cubic zirconia is lab-created by melting zirconium oxide powders stabilized with magnesium and calcium at very high temperatures, then allowing crystals to form and stabilize before cutting and polishing

. It is commonly used in various jewelry items such as rings, earrings, necklaces, and bracelets, offering an affordable and visually attractive alternative to diamonds

. In summary, cubic zirconia is a man-made, hard, and usually colorless gemstone that mimics the appearance of diamonds but differs in composition, hardness, density, and optical properties