Hureaulite: Gemstone Information
Hureaulite is Mn2 5 (PO4)2(PO3OH)24H2O and forms transparent to translucent light rose to pink to rose-violet, orange or yellowish brown long to short prismatic elongated monoclinic crystals with a somewhat greasy lustre, hardness 3.5 and SG 3.19. The RI for the alpha, beta and gamma rays is 1.647–1.654, 1.654–1.662 and 1.660–1.667 with birefringence 0.012. Hureaulite occurs as a late-stage secondary mineral formed by the alteration of primary phosphates in complex granite pegmatites. Possible ornamental material from Branchville, Fairfield County, Connecticut and from the Fletcher and Palermo #1mines, North Groton, Grafton County,New Hampshire, USA.