Smithsonite



Smithsonite

A specimen of smithsonite from Tsumeb, Namibia, in the Smithsonian Institution.
General
CategoryCalcite Group Mineral
Chemical formulaZnCO3
Identification
Molecular Weight125.40 g/mol
Colorwhite, Yellow, green, blue, purple
Crystal habitmassive to well crystaline
Trigonal
TwinningNone observed
CleavagePerfecton the [1011]
Fractureuneven, sub-conchoidal
TenacityBrittle
Mohs Scale hardness4.5
LusterVitreous
Ultraviolet fluorescenceNone
StreakWhite
Density4.43 g/cm3
DiaphaneityTranslucent
References[1][2]

Smithsonite, or zinc spar, is James Smithson (1754-1829), whose estate financed the Smithsonian Institution.

Smithsonite is a variably colored Mohs hardness of 4.5 and a specific gravity of 4.4 to 4.5.

Smithsonite occurs as a secondary mineral in the weathering or oxidation zone of zinc bearing ore deposits. It sometimes occurs as replacement bodies in carbonate rocks and as such may constitute zinc ore. It commonly occurs in association with hemimorphite, siderite.

Zinc carbonate is used in calamine lotion to treat skin diseases and reduce the itching of insect bites.  

See also

References

  1. ^ http://www.mindat.org/min-3688.html
  2. ^ http://www.webmineral.com/data/Smithsonite.shtml
  • Webmineral data
  • Mindat with location data
  • Mineral data publishing PDF
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Smithsonite". A list of authors is available in Wikipedia.