CORUNDUM SYNTHETIC RUBY #5 Loose Stones Gems - 2.0 MM
CORUNDUM SYNTHETIC Stone Loose – 2.0 MM. Cubic Zirconia is a substitute for Diamond. It is made of a synthetic material that is not as hard as diamond. Comparing hardness, Zirconia is an 8.5 hardnes while Diamond is a 10 on the Mohs scale.