Bílinite

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Bílinite
General
Category Sulfate mineral
Formula
(repeating unit)
Fe2+Fe3+2(SO4)·22H2O
Strunz classification 07.CB.85
Dana classification 29.07.03.05
Identification
Color White to yellowish
Crystal habit Fibrous in radial aggregates
Crystal system Monoclinic - prismatic (2/m)
Mohs scale hardness 2
Luster Vitreous - silky
Streak White
Diaphaneity Semitransparent
Specific gravity 1.87
Optical properties Biaxial (+/-)
Refractive index nα = 1.480 - 1.482 nβ = 1.500 nγ = 1.489 - 1.493
Birefringence δ = 0.009 - 0.011
Solubility Soluble in water
References [1][2][3]

Bílinite (Fe2+Fe23+(SO4)·22H2O) is an iron sulfate mineral. It is a product of the oxidation of pyrite in water. It is an acidic mineral that has a pH of less than 3 and is harmful to the environment when it comes from acid rock drainage (Keith et al., 2001).

Bílinite was first discovered near Bílina, Czech Republic which is why the mineral was named 'bílinite' (Palache, et al., 1969). This mineral possibly occurs on Mars.

Composition[edit]

The weight percent oxide is as follows:[1]

Oxide Composition
SO3 33.78
Fe2O3 16.84
FeO 7.58
H2O 41.8
Total 100

Related minerals[edit]

Related minerals to bílinite include jarosite, which is an iron sulfate salt, lepidocrocite, schwetmannite, ferricopiapite, and copiapite (Marion, et al., 2008).

Special characteristics[edit]

Boulder Creek is a stream at Iron Mountain in Shasta County, California. The stream drains into the Sacramento River and San Francisco Bay. The water in this stream is contaminated from the mixture of the groundwater and surface streams due to mining. The pH is low and acidic due to the oxidation of pyrite in water. This results in the formation of sulfuric acid and bílinite (Keith, et al., 2001).

References[edit]

  • Keith, David C., Runnells, Donald D., Esposito, Kenneth J., Chermak, John A., Levy, David B., Haaula, Steven R., Watts, Malcolm, Hall, Larry. (2001) Geochemical models of the impact of acidic groundwater and evaporative sulfate salts on Boulder Creek at Iron Mountain, California. Applied Geochemistry 16, 947-961.
  • Marion, Giles M., Kargel, Jeffrey S., Catling, David C. (2008) Modeling ferrous-ferric iron chemistry with application to Martian surface geochemistry. Geochimica Et cosmochimica Acta 72, 242-266.
  • Tosca, Nicholas J, McLennan Scott, M, (2009) Experimental constraints on the evaporation of partially oxidized acid-sulfate waters at the martian surface. Geochimica Et Cosmochmica Acta 73, 1205–1222.
  • Palache, C. H,. Berman, and C. Frondel, Bol'shakov, A.P. And L.I. Ptushko (1951) Fe2+ Fe23+ (SO4)4 *22(H2O). Handbook of Mineralogy. Mineral Data Publishing (Republish by the Mineralogical Society of America).