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Description:
Geological Survey of Western Australia, Perth 1994.
Department of Minerals and Energy.

In Western Australia there is an abundance of
semiprecious stones (which are any gemstones other
than precious stones), particularly those composed
of silica in both amorphous (opaline) and cryptocrystalline
forms. Both professional and amateur
collectors and lapidaries have ample scope to pursue
their interests.

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