Samarskite
1231165
211802244
2008-05-12T04:28:17Z
Tillman
1663062
2nd photo
[[Image:Samarskite.jpg |thumb|'''Samarskite''', [[Mitchell County]], [[North Carolina]] ]]
[[Image:Samarskite-fresh.jpg|thumb|'''Samarskite''' specimen, broken to show fresh surface]]
'''Samarskite''' or properly '''samarskite-(Y)''' is a [[radioactive]] [[mineral]] with the [[empirical formula]]:
:[[Yttrium|Y]]<sub>0.2</sub>[[Rare Earth Element|REE]]<sub>0.3</sub>[[Iron|Fe<sup>3+</sup>]]<sub>0.3</sub>[[Uranium|U]]<sub>0.2</sub>[[Niobium|Nb]]<sub>0.8</sub>[[Tantalum|Ta]]<sub>0.2</sub>[[Oxide|O]]<sub>4</sub><ref>[http://webmineral.com/data/Samarskite-(Y).shtml Webmineral data]</ref>
Other formulas show Ce ([[cerium]]) rather than the generic REE ([[Rare earth element]]) and include essential [[titanium]].
*(Y,Ce,U,Fe)<sub>3</sub>(Nb,Ta,Ti)<sub>5</sub>O<sub>16</sub><ref name="WMClark">{{cite web | title=THE MINERAL SAMARSKITE-(Y) | publisher = Amethyst Galleries, Inc. | date = 1997 | url = http://www.galleries.com/minerals/oxides/samarski/samarski.htm | accessdate = 2006-08-19 }}</ref><ref>[http://www.uraniumminerals.com/UTh/Samarskite.htm Uranium minerals data]></ref>
*YFe<sup>3+</sup>Nb<sub>2</sub>O<sub>8</sub><ref>[http://www.mindat.org/min-3512.html Mindat]</ref>
*(Y,Fe<sup>3+</sup>,U)(Nb,Ta)O<sub>4</sub><ref>[http://rruff.geo.arizona.edu/doclib/hom/samarskitey.pdf Mineral Data Publishing]</ref>
Samarskite crystallizes in the [[orthorhombic]] - dipyramidal class as black to yellowish brown stubby prisms although it is typically found as [[Anhedral (petrology)|anhedral]] masses. It has a [[Mohs hardness]] of 5 to 6 and a widely variable [[specific gravity]] of 4.3 - 5.87. Specimens with a high uranium content are typically [[metamict]] and appear coated with a yellow brown earthy rind. Samarskite occurs in [[granite]] [[pegmatite]]s with other rare minerals.
Samarskite was first described in 1847 for an occurrence in [[Miass]], Ilmen Mountains, Southern [[Ural Mountains]] of [[Russia]]. The chemical element [[samarium]] was first isolated from a specimen of samarskite in 1879. Samarskite and samarium were named for the Russian mine official, Colonel [[Vasili Samarsky-Bykhovets]] (1803-1870).
==See also==
*[[List of minerals]]
*[[List of minerals named after people]]
==References==
<references/>
{{mineral-stub}}
[[Category:Uranium minerals]]
[[Category:Yttrium minerals]]
[[Category:Lanthanide minerals]]
[[Category:Iron minerals]]
[[Category:Niobium minerals]]
[[Category:Tantalum minerals]]
[[Category:Oxide minerals]]
[[de:Samarskit]]
[[it:Samarskite-(Y)]]
[[pt:Samarskita]]