Sarkinite

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Sarkinite
Sarkinite-MD-18492a.jpg
General
Category Arsenate minerals
Formula
(repeating unit)
Mn2(AsO4)(OH)[1]
Strunz classification 8.BB.15[1]
Dana classification 41.6.3.3[1]
Crystal system Monoclinic
Crystal class Prismatic (2/m)
(same H-M symbol)
Space group P2m[1]
Unit cell a = 12.7795(13) Å
b = 13.6127(14) Å
c = 10.2188(11) Å
β = 108.834(2)°; Z = 16[1]
Identification
Color Red to yellow[1]
Crystal habit Tabular[2] or granular[1]
Cleavage Distinct on {100}[1]
Fracture Irregular/Uneven, Conchoidal[1]
Mohs scale hardness 4–5[1]
Luster Greasy[1]
Streak Red to yellow[1]
Diaphaneity Semitransparent[3]
Density 4.08 to 4.18 g/cm3 (measured)[1]
Optical properties Biaxial (-)[1]
Refractive index nα=1.793, nβ=1.807, nγ=1.809[1]
Birefringence δ = 0.016[1]
Pleochroism Weak[1]
2V angle 83° (measured)[1]
Dispersion r > v or r < v[1]
Absorption spectra X > Z > Y[1]
Solubility Readily soluble in dilute acids[1]

Sarkinite, synonymous with chondrarsenite and polyarsenite, is a mineral with formula Mn2(AsO4)(OH). The mineral is named for the Greek word σάρκιυος, meaning made of flesh, for its red color and greasy luster. The mineral was first noted in Sweden in 1865 as chondrarsenite, though not identified as Sarkinite until 1885.

Description[edit]

Sarkinite is red to yellow in color. It occurs as thick tabular crystals, short prismatic crystals, or has a granular habit. Sarkinite sometimes aggregates into a roughly spherical shape. Sarkinite is a member of the Wagnerite Group.[1]

The mineral occurs in manganese-rich lenses in quartzitic chlorite schists, metamorphosed zinc ore bodies, and rarely in metamorphosed FeMn ore bodies.[3]

Structure[edit]

Sarkinite is isostructural with triploidite and wolfeite[1] and is a dimorph of eveite.[4] The crystal structure consists of MnO4(OH)2 octahedra, MnO4(OH) trigonal bipyramids, and AsO4 tetrahedra.[5]

History[edit]

In 1885, two similar minerals were discovered in Sweden. Polyarsenite was found in Grythyttan and named by Igelström for its high arsenic content. Sarkinite was discovered in Pajsberg, Persberg, and named by A. Sjögren after the Greek word σάρκιυος, meaning made of flesh, in reference to the blood-red color and greasy luster. It was considered likely that the two minerals were identical.[6] A study in 1980 showed that polyarsenite and chondrarsenite, discovered in 1865, were in fact both sarkinite.[7]

Distribution[edit]

As of 2012, sarkinite has been found in Austria, France, Italy, Japan, Kazakhstan, Romania, Sweden, Switzerland, and the United States.[1]

Association[edit]

Sarkinite has been found in association with:[3]

Harstigen mine, Sweden

Sjö mine, Sweden

Ködnitz Valley, Austria

Falotta mine, Switzerland

Sterling Hill, New Jersey, US

References[edit]

  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x "Sarkinite". Mindat. Retrieved May 28, 2012. 
  2. ^ "Sarkinite". Webmineral. Retrieved May 29, 2012. 
  3. ^ a b c "Sarkinite" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Retrieved May 30, 2012. 
  4. ^ Halenius, p. 113.
  5. ^ Dal Negro, p. 246.
  6. ^ Smithsonian Institution (1886). Annual Report of the Board of Regents of the Smithsonian Institution Showing the Operations, Expenditures, and Condition of the Institution to July, 1885 (Report). Government Printing Office. p. 701. 
  7. ^ Dunn, Pete J. (March 1980). "On the composition of some sarkinites" (PDF). Mineralogical Magazine. 43 (329): 681. doi:10.1180/minmag.1980.043.329.22. Retrieved May 29, 2012. 

Bibliography[edit]

External links[edit]

Media related to Sarkinite at Wikimedia Commons