Lazulite: Gemstone Information
In recent years, fine transparent blue crystals of lazulite have been found and fashioned. Lazulite is MgAl2(PO4)2(OH)2 and occurs as stubby to acute dipyramidal crystals of the monoclinic system with hardness 5.5–6 and SG 3.122–3.240. The RI of the alpha, beta and gamma rays is 1.604–1.626,1.626–1.654 and 1.637–1.663, biaxial negative with birefringence 0.031–0.036.It is strongly pleochroic in dark blue, light blue and colourless directions.Lazulite occurs in granite pegmatites and in quartzites. Fine blue transparent lazulite may resemble Paraíba tourmaline (q.v.), this material originating probably from west of Dattas, Minas Gerais, Brazil. Fine green material is also found in the Chilas area of the northern areas of Pakistan and Angola is another possible source. Lazulite forms a series to scorzalite (q.v.).