Labgrown Diamonds Vs Cubic Zirconia Key Differences Explained

The jewelry market is flooded with dazzling stone options—natural diamonds, lab-grown diamonds, cubic zirconia—leaving many consumers confused about their differences. As ethical concerns about "blood diamonds" grow, more shoppers are turning to lab-created alternatives. However, some sellers are passing off cubic zirconia (CZ) as genuine diamonds, leaving buyers with inferior products at inflated prices.

Cubic zirconia is a synthetic material that closely resembles diamonds in appearance. Composed of zirconium dioxide with a cubic crystal structure, CZ is artificially created to be colorless, hard, and flawless. Since its introduction in 1976, CZ has gained popularity as an affordable diamond substitute in jewelry. Manufacturers can also add various chemical elements to create colored versions that mimic rare fancy diamonds.

CZ was originally developed in the 1970s by Soviet scientists for laser applications, not jewelry. Its exceptional optical properties made it valuable for technical uses. The gemstone industry later adopted CZ when its diamond-like brilliance and low production costs were discovered. Today, CZ appears in various jewelry pieces including engagement rings, necklaces, and earrings.

Despite visual similarities, CZ lacks the chemical composition and physical properties of genuine diamonds. On the Mohs hardness scale, CZ ranks at 8.5 compared to diamond's perfect 10. While CZ can be cut into diamond shapes and displays similar sparkle, it remains an imitation rather than the real thing.

Lab-grown diamonds share identical chemical and physical properties with natural diamonds—both are pure carbon crystallized in a cubic structure. CZ, however, is zirconium dioxide with different optical characteristics. Diamonds have a refractive index of 2.42 compared to CZ's 2.15-2.18, and exhibit different light dispersion patterns (0.044 for diamonds vs. 0.058-0.066 for CZ).

Lab diamonds are "grown" using two primary methods: High Pressure High Temperature (HPHT) or Chemical Vapor Deposition (CVD). Both processes replicate natural diamond formation using carbon atoms that build upon diamond seed crystals over 10-12 weeks. CZ production involves melting powdered zirconium and zirconium dioxide at extreme temperatures (about 2,750°C) to form synthetic crystals—a fundamentally different process.

While CZ typically appears flawless (equivalent to a D-color diamond), this perfection can appear unnatural compared to most lab-grown diamonds which often show slight color tints. Under magnification, CJ's softer composition results in more rounded facet edges compared to the sharp, precise cuts of genuine diamonds.

With superior hardness and wear resistance, lab-grown diamonds offer greater longevity than CZ. This durability difference, along with the fact that lab diamonds are actual diamonds, explains their significantly higher price points compared to CZ jewelry.

The lab-grown diamond market has shown consistent growth, projected to expand from $1.62 billion in 2016 to $2.76 billion by 2023. Meanwhile, CZ sales have fluctuated as educated consumers increasingly prefer authentic diamond alternatives that combine ethical sourcing with genuine quality.

When purchasing diamond jewelry, experts recommend verifying the stone's origin and characteristics through reputable certification. Understanding these material differences helps consumers make informed choices that align with their values and expectations.