Samarskite-(Y): Gemstone Information
Samarskite-(Y) is found either as characteristically rough crystals or as opaque granular, velvet-black masses which may be externally yellowish brown. Samarskite is orthorhombic and metamict; the hardness is 5–6 and the SG 5.0–5.69; the RI is 2.1–2.2, the mineral behaving as if isotropic.Samarskite occurs as an accessory mineral in rare earth-rich granite pegmatites. Caochons may come from any of a number of localities,including Miass, Ilmen Mountains, Russia. Samarskite’s composition is spelt out in Fleischer’s Glossary of Mineral Species 2004 (passim).