Facts about opal
The chemical composition of opal is SiO2 n H2O
90% of the world’s opal is found in Australia.
Opal is the national gemstone of Australia.
It is thought opal formed one hundred million years ago at the beginning of the Cretaceous Period.
A solid opal can be worn in water.
The hardness of opal is 5.5 – 6.5 on Moh’s scale of hardness.
Every opal is unique.