Goslarite

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Goslarite
General
Category Sulfate mineral
Formula
(repeating unit)
ZnSO4·7(H2O)
Strunz classification 07.CB.40
Crystal symmetry Orthorhombic disphenoidal
H-M symbol: (2 2 2)
Space group: P 212121
Unit cell a = 11.8176 Å, b = 12.0755 Å, c = 6.827 Å, Z = 4
Identification
Formula mass 287.56 g
Color Colorless, pinkish, white, greenish, green, blue, green blue, bluish and brownish
Crystal habit Acicular, massive, stalactitic
Crystal system Orthorhombic
Cleavage {010} perfect
Fracture Conchoidal
Tenacity Brittle
Mohs scale hardness 2.0–2.5
Luster Vitreous (glassy)
Streak White
Specific gravity 1.96
Optical properties Biaxial (-)
Refractive index nα = 1.447 - 1.463 nβ = 1.475 - 1.480 nγ = 1.470 - 1.485
Birefringence δ = 0.0220–0.0230
Pleochroism none
2V angle 46°
References [1][2][3][4]

Goslarite is a hydrated zinc sulfate mineral (ZnSO4·7(H2O)) which was first found in the Rammelsberg mine, Goslar, Harz, Germany. It was described in 1847. Goslarite belongs to the epsomite group which also includes epsomite (MgSO4·7H2O) and morenosite (NiSO4·7H2O). Goslarite is an unstable mineral at the surface and will dehydrate to other minerals like bianchite (ZnSO4·6H2O), boyleite (ZnSO4·4H2O) and gunningite (ZnSO4·H2O).

Physical properties[edit]

The composition of goslarite was determined by the US national bureau of standards in 1959 as follows: SO3 27.84 wt%, ZnO 28.30 wt% and H2O 43.86 wt%.

Goslarite's cleavage is perfect in {010}, as for epsomite and morenosite. The color of goslarite ranges from brownish to pinkish, blue, brown, colorless, green and green blue. The luster ranges from vitreous to nacreous and silky (if fibrous). Goslarite is soluble in water, has an astringent taste, and is strongly diamagnetic.[5][6][7]

Geologic occurrence[edit]

Goslarite is formed from the oxidation of sphalerite ((Zn, Fe)S).[8] It was first found in Rammelsberg mine, Goslar, Harz, Germany. It often occurs as an efflorescence on timbers and walls of mine passages. Goslarite is widespread as a post mining efflorescence in mines that contain sphalerite or any zinc minerals.

Economical uses[edit]

In the pharmaceutical industry it is used as a direct emetic, antiseptic and disinfectant.[9]

References[edit]

  1. ^ Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W. and Nichols, Monte C. (ed.). "goslarite" (PDF). Handbook of Mineralogy. Chantilly, VA, US: Mineralogical Society of America. ISBN 0962209716. 
  2. ^ Goslarite on Mindat
  3. ^ Goslarite data on Webmineral
  4. ^ Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., ISBN 0-471-80580-7
  5. ^ Dana, J.D. (1854). A System of Mineralogy Comprising The Most Recent Discoveries. New York: Putnam. p. 384. 
  6. ^ Egleston, T (1871). Catalogue of Minerals, with Their Formulae and Crystalline Systems: Prepared for the Use of the Students of the School of Mines, of Columbia College. Columbia: Angell. p. 173. 
  7. ^ Palache (1944). The System of Mineralogy. New York: John Wiley & Sons. pp. 513–516. 
  8. ^ Gaines, RV (1997). Dana's New Mineralogy. New York: John Wiley & Sons. p. 819. ISBN 0471193100. 
  9. ^ Carretero, MI (2009). "Clay and non-clay minerals in the pharmaceutical and cosmetic industries Part II. Active ingredients". Applied Clay Science 47 (3–4): 171–181. doi:10.1016/j.clay.2009.10.016. 

External links[edit]