Samarskite

Formula: (YFe³⁺Fe²⁺U,Th,Ca)₂(Nb,Ta)₂O₈Mohs scale hardness: 5–6Specific gravity: 5,6-5,8 g/cm³Rare earth elements: Y, La, Ce, Pr, Nd, Er ^{Rare earth content, %: Y}2^O3 ^{6.4–14.5; Er}2^O3 ^{2.7–13.4; Ce}2^O3 ^{0.25–3.2; La}2^O3 ^{0.37–1; (Pr,Nd)}2^O3 ^{0.74–4.2; REO}max^{=16,6 %}

Other constituents, %: Nb2O5 2.7–46.8; Ta2O5 1.8–27; ThO2 0–4.2; UO2 4–16, Ti, Zr, Sn

^{Mineralklasse: Oxide and Hydroxides}

Uses: A minor ore of rare earth elements and uranium, sometimes cut as a gemstone and as mineral specimens.

Samarskite is a radioactive rare earth mineral. Samarskite occurs in rare earth bearing granite pegmatites with other rare minerals.

Association: Columbite, zircon, monazite, uraninite, aeschynite, magnetite, albite, topaz, beryl, garnet, muscovite, biotite.

Distribution: A few localities for analyzed material include: at Miass, Ilmen Mountains, Southern Ural Mountains, Russia. From the Anner ̈od, Iveland, and Setesdal districts, Norway. In the USA, at Glastonbury, Hartford Co., Connecticut; in the Mitchell pegmatite, Bedford Co., Virginia; around Spruce Pine, Mitchell Co., North Carolina; near Nuevo, Riverside Co., California; at the Addey claims, along Texas Creek, Fremont Co., Colorado; and in the New Year’s Eve mine,

Sierrita Mountains, Pima Co., Arizona. At Divina de Uba, near Belo Horizonte, Minas Gerais, Brazil. In Madagascar, from Ambatofotsikely, Antsirabe, Ampangab ́e, and elsewhere. At Kivu, Kivu Province, Congo (Zaire). In Japan, especially in the Ishikawa district, Fukushima Prefecture. Many other localities are known.

References

1. https://en.wikipedia.org

2. https://en.wikipedia.org/wiki/Samarskite-%28Y%29

3. http://www.mindat.org/min-3512.html

4. http://webmineral.com/data/Samarskite-%28Y%29.shtml#.V0e10-Q8vYg

5. http://www.handbookofmineralogy.org/pdfs/samarskite-%28Y%29.pdf

6. http://www.galleries.com/Samarskite

7. http://webmineral.com/specimens/picshow.php?id=3146#.V0e6guQ8vYg

8. http://mrdata.usgs.gov/ree/ree.php?mineral=samarskite