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(Redirected from Samarskite)
CategoryOxide minerals
(repeating unit)
IMA symbolSmk-Y[1]
Strunz classification4.DB.25
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPbcn
Unit cella = 5.687 Å, b = 4.925 Å
c = 5.21 Å; Z = 2
ColorBlack, may have a brownish tint, brown to yellowish brown due to alteration; light to dark brown in transmitted light
Crystal habitCrystals elongated with pyramidal terminations; commonly granular to massive
Cleavage{010}, indistinct
FractureConchoidal fragments
Mohs scale hardness5–6
LusterVitreous – resinous
StreakReddish brown
DiaphaneityOpaque, transparent in thin fragments
Density5.6 – 5.8, Average = 5.69
Optical propertiesAppears isotropic
Refractive indexn = 2.1–2.2
Alters toMetamict
Other characteristics Radioactive (Greater than 70 Bq / gram)

Samarskite is a radioactive rare earth mineral series which includes samarskite-(Y), with the chemical formula (YFe3+Fe2+U,Th,Ca)2(Nb,Ta)2O8[3] and samarskite-(Yb), with the chemical formula (YbFe3+)2(Nb,Ta)2O8.[6] The formula for samarskite-(Y) is also given as (Y,Fe3+,U)(Nb,Ta)O4.[5]

Samarskite crystallizes in the orthorhombic – dipyramidal class as black to yellowish brown stubby prisms although it is typically found as anhedral masses. Specimens with a high uranium content are typically metamict and appear coated with a yellow brown earthy rind.

Samarskite occurs in rare earth bearing granite pegmatites with other rare minerals. It occurs in association with columbite, zircon, monazite, uraninite, aeschynite, magnetite, albite, topaz, beryl, garnet, muscovite and biotite.[5]

Samarskite was first described in 1847 for an occurrence in Miass, Ilmen Mountains, Southern Ural Mountains of Russia.[4] The chemical element samarium was first isolated from a specimen of samarskite in 1879. Samarium was named after samarskite which was named for the Russian mine official, Colonel Vasili Samarsky-Bykhovets (1803–1870).[4]

Samarskite-(Yb) was first described in 2004 for an occurrence in the South Platte Pegmatite District, Jefferson County, Colorado.[6][7]

Samarskite specimen, broken to show fresh surface

See also[edit]


  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Samarskite-%28Y%29 Archived 2019-08-11 at the Wayback Machine Mineralienatlas
  3. ^ a b "Mindat Samarskite-(Y)". Archived from the original on 2006-09-08. Retrieved 2006-08-20.
  4. ^ a b c http://webmineral.com/data/Samarskite-(Y).shtml Archived 2011-05-14 at the Wayback Machine Webminerals
  5. ^ a b c "Handbook of Mineralogy" (PDF). Archived (PDF) from the original on 2006-09-12. Retrieved 2006-08-20.
  6. ^ a b "Mindat Samarskite-(Yb)". Archived from the original on 2010-12-23. Retrieved 2011-02-22.
  7. ^ "Samarskite-(Yb) on Webmineral". Archived from the original on 2011-06-29. Retrieved 2011-02-22.