Samarskite-(Y)
Samarskite-(Y) is one of several Rare Earth Oxides. Other rare earth oxides such as Fergusonite and Euxenite-(Y) have very similar properties to Samarskite-(Y) and are often associated with each other. Samarskite-(Y) is a radioactive due to its uranium and cerium content and should be handled and stored carefully – human exposure should be very limited!
The few localities for analyzed material include: at Miass, Ilmen Mountains, Southern Ural Mountains, Russia. From the Ånneröd, Iveland, and Setesdal districts, Norway. In the USA, at Glastonbury, Hartford County, Connecticut; in the Mitchell pegmatite, Bedford County, Virginia; around Spruce Pine, Mitchell County, North Carolina; near Nuevo, Riverside County, California; at the Addey claims, along Texas Creek, Fremont County, Colorado; and in the New Year’s Eve mine, Sierrita Mountains, Pima County, Arizona. At Divéina de Uba, near Belo Horizonte, Minas Gerais, Brazil. In Madagascar, from Ambatofotsikely, Antsirabe, Ampangab, and elsewhere. At Kivu, Kivu Province, Congo (Zaire). In Japan, especially in the Ishikawa district, Fukushima Prefecture. Many other localities are known.
| Chemical Formula: | (Y,Fe3+,U)(Nb,Ta)O4 |
| Yttrium Cerium Uranium Iron Niobium Tantalum Titanium Oxide | |
| Molecular Weight: | 299.85 gm |
| Composition: | La,Ce,Pr,Nd,Sm | 14.41 % | RE | 16.81 % | REE2O3 |
| Yttrium | 5.93 % | Y | 7.53 % | Y2O3 | |
| Uranium | 15.88 % | U | 18.01 % | UO2 | |
| Tantalum | 12.07 % | Ta | 14.74 % | Ta2O5 | |
| Niobium | 24.79 % | Nb | 35.46 % | Nb2O5 | |
| Iron | 5.59 % | Fe | 7.99 % | Fe2O3 | |
| Oxygen | 21.34 % | O | |||
| 100.00 % | 100.00 % | = TOTAL OXIDE |
| Crystallography: | Orthorhombic – Dipyramidal |
| Crystal Habit: | Crystals, typically rough, elongated || [001], to 12 cm, pyramidal terminations, cross-sections rectangular, flattened on {100} or {010}; commonly granular, massive. |
| Twinning: | None |
| Cleavage: | {010} Indistinct |
| Fracture: | Concoidal to small Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 5.0 – 6.0; (VHN = 736–897) |
| Density: | 5.00 – 5.69 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Very Strong; GRapi = 1,202,300.20 (Gamma Ray American Petroleum Institute Units) |
| Health Warning: | Contains uranium – always wash hands after handling. Avoid inhaling dust when handling or breaking. Never lick or ingest. Avoid prolonged exposure in proximity of the body. Store away from inhabited areas. |
| Color: | Velvet-black, may have a Brownish tint, Brown to Yellowish Brown due to alteration; light to dark Brown in transmitted light |
| Transparency: | Opaque, Transparent in thin fragments |
| Luster: | Vitreous, Resinous, Sub-Metallic, externally Dull |
| Refractive Index: | n = 2.1 – 2.2 Isotropic |
| Birefringence: | 0.000; Isotropic minerals have no birefringence |
