Augelite: Gemstone Information

Colourless to yellowish, pale rose or pale blue crystals of augelite, A12 (PO4)(OH)3, have been fashioned. The monoclinic crystals have a tabular habit, a hardness of 5 and an SG near to 2.7. The RIs are 1.574, 1.576 and 1.588. The mineral is biaxial and optically positive with a birefrin-gence of 0.014. The stones have a vitreous lustre and show no lumines-cence under either form of UV. Augelite is found at White Mountain,California, in Bolivia and in Spain. Material from California has RIs of 1.570–1.575 and 1.590–1.591, with a birefringence of 0.02. Large crystals have been found at the Champion mine, Mono County, California;. some have been fashioned but the source has been reported to be exhausted