The Lab Gem Supplier

Of all the materials used to simulate natural diamonds, cubic zirconia is the most successful with a visual appearance usually indistinguishable from nature’s most valuable gem creation. While created in the lab, cubic zirconia does exist in minute, commercially irrelevant amounts in nature. A cubic crystalline form of zirconium dioxide with the same isometric crystallography as diamonds, cz is denser, nearly as hard, almost as refractive with the same luster and a higher dispersion than natural diamonds.

Viable cubic zirconia was created in the lab in 1930. Interestingly, in 1937 naturally occurring microscopic grains of cz were discovered in metamict zircon by German mineralogists M.V. Stackelberg and K. Chudoba who believed cz to be a product of the metamictization process. Metamictization is the naturally occurring destruction of a mineral’s crystal structure through internal bombardment by radioactive impurities.

Cubic zirconia was first produced for economic use in lasers and other technical optical applications. Because of its extremely high melting point, production was problematic until the perfection of the cold crucible technique by Soviet scientists in the 1970s. Commercial production of cz took off in 1976 and improvements have continued. Loose cubic zirconia are now available in a wide variety of quality and colors from cz wholesalers.

Besides its affordable price, key features that distinguish cubic zirconia from diamonds include:

• CZ is 1.6 times denser and therefore heavier than diamond with a higher specific gravity, 5.6 to 6.0.
• Harder than most natural gems and nearly as hard as diamond’s 10, cz registers 8 on the Mohs scale.
• With a refractive index of 2.17, cz is nearly as refractive as diamond which has an index of 2.42.
• Both cz and diamond exhibit subadamantine luster.
• CZ has an exceptionally high dispersion, 0.060, compared to diamond at 0.044, producing greater prismatic fire.
• Completely colorless AAAAA cubic zirconia, comparable to a perfect D on the diamond color grading scale, can be created in the lab whereas most diamonds contain yellow or brown flaws.

Weight and the fact that cubic zirconia is a thermal insulator while diamond is a thermal conductor are the two easiest ways to distinguish cz from diamonds. On looks alone, the two appear identical.