Triphylite is the iron end member of the Lithiophilite-Triphylite Series and isostructural with olivine. It is a lithium iron phosphate. It is usually massive, but it rarely forms greenish-gray to dark brown, resinous to vitreous, orthorhombic, stout prismatic, translucent crystals with rough faces. It was named in 1834 by Johann Nepomuk von Fuchs from the Greek word, "tria", (threefold), and "phylon", (family), because it was thought to contain three cations (Fe, Li, Mn). The type locality for triphylite is Hennenkobel mine, Rabenstein, Zwiesel, Lower Bavaria, Bavaria, Germany. Triphylite occurs as a primary mineral in granite pegmatites; it is often completely altered to a variety of secondary phosphates. Some notable localities include: Newry, Oxford Co., and Estes quarry, Cumberland Co., both in Maine, USA; the Palermo No.1 mine, Grafton Co., and Newport, Sullivan Co., in New Hampshire, USA; the Tip Top and Bull Moose mines in Custer Co., and at Keystone, Pennington Co., all of South Dakota, USA. Other world-wide regions where Li pegmatites occur include: Galileia region, Minas Gerais, Brazil. Bohemia, Czech Republic; Bavaria, Germany; Haute-Vienne dept., France; Triphylite occurs less commonly in pegmatites of Sweden and Bolivia.
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