Fluorite
Fluorite is a calcium fluoride that crystallises in the cubic system. It occurs in a wide range of attractive colours. However a hardness of 4, perfect octahedral cleavage and a sensitivity to sudden changes in temperature make it difficult to facet and preserve. Although rarely used in jewellery fluorite is faceted as a collector's stone.
Australia
In New South Wales, attractive emerald-green fluorite comes from Emmaville, in the New England district. Attractive fluorite crystals are found at Luina, Tasmania.