Tripuhyite

Tripuhyite
General
Category Antimonate mineral
Formula
(repeating unit)		 FeSbO4
Strunz classification 4.DB.05
Crystal system Tetragonal
Unit cell a = 4.63, c = 9.14 [Å]; Z = 2
Identification
Color Yellowish brown, lemon-yellow, brown-black
Crystal habit Fibrous to fine-grained aggregates
Crystal symmetry Tetragonal - ditetragonal dipyramidal
H-M symbol (4/m 2/m 2/m)
Space group: P 41/mnm
Mohs scale hardness 6 - 7
Luster Dull to earthy
Streak Canary-yellow to dark brown with a greenish tinge
Diaphaneity Translucent
Specific gravity 5.82
Optical properties Uniaxial (+)
Refractive index nω = 2.190 nε = 2.330
Birefringence δ = 0.140
Other characteristics Antiferromagnetic
References [1][2][3]

Tripuhyite is an iron antimonate mineral with composition FeSbO4.

Nomenclature

The name of the mineral comes from the localilty of Tripuhy, Ouro Preto, Minas Gerais, Brazil, where it was discovered. Hussak and Prior[4] first described the mineral tripuhyite as an oxide of iron and antimony, and assigned it the composition Fe2Sb2O7. When a mineral with composition FeSbO4 was later discovered in Squaw Creek, New Mexico (US), it was considered erroneously as a new mineral and it was given the name squawcreekite.[5] However, other studies had shown that the original tripuhyite was also FeSbO4.[6] In 2002, the Commission on New Minerals and Mineral Names (CNMMN) of the International Mineralogical Association (IMA), approved the redefinition of tripuhyite as FeSbO4 and the discreditation of squawcreekite.[7]

Crystal Structure

FeSbO4 exhibits the rutile structure, with a tetragonal unit cell. The cations are octahedrally coordinated to oxygen anions, with the octahedra sharing edges along the c-direction. Fe(III) and Sb(V) cations are distributed in a disordered way over the octahedral sites.

References

  1. ↑ Mindat.org
  2. ↑ Handbook of Mineralogy
  3. ↑ Webmineral data
  4. ↑ Hussak, E.; Prior, G. T. (1897). "On Tripuhyite, a New Antimonate of Iron, from Tripuhy, Brazil". Mineralogical Magazine 11: 302–303. doi:10.1180/minmag.1897.011.53.04.
  5. ↑ Foord, E. E.; P. F. Hlava; J. J. Fitzpatrick; R. C. Erd; R. W. Hinton (1991). Neues Jahrbuch Fur Mineralogie-Monatshefte 8: 363–384. Missing or empty |title= (help)
  6. ↑ Tavora, E. (1955). "X-ray diffraction powder data for some minerals from Brazilian localities". Anais da Academia Brasileira de Ciencias 27: 7–27.
  7. ↑ Berlepsch, P.; T. Armbruster; J. Brugger; A. J. Criddle; S. Graeser (2003). "Tripuhyite, FeSbO4, revisited.". Mineralogical Magazine 67: 31–46. doi:10.1180/0026461036710082.


This article is issued from Wikipedia - version of the Thursday, April 21, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.