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Germanite
Germanite, probably from the Tsumeb Mine, Otjikoto Region, Namibia. Specimen size 5 cm
General
CategorySulphide mineral
Formula
(repeating unit)
Cu26Ge4Fe4S32[1]
Strunz classification2/C.10.20
Dana classification2.9.4.2
Crystal systemIsometric B43m
Identification
Formula mass3,192.14 g
ColorReddish grey tarnishing to dark brown
Crystal habitUsually massive; rarely as minute cubic crystals
CleavageNone
TenacityBrittle
Mohs scale hardness4
LusterMetallic
StreakDark grey to black
DiaphaneityOpaque[2]
Specific gravity4.4 to 4.6
Density4.47
Other characteristicsCell data: a = 10.585
Z = 1

Germanite is a rare copper iron germanium sulfide mineral, Cu26Fe4Ge4S32. It was first discovered in 1922, and named for its germanium content. It is only a minor source of this important semiconductor element, which is mainly derived from the processing of the zinc sulphide mineral sphalerite[3]. Germanite contains gallium Ga, zinc Zn, molybdenum Mo, arsenic As, and vanadium V as impurities. It's type locality (the place where it was first desribed) is the Tsumeb Mine in Namibia, and it has also been reported from Argentina, Armenia, Bulgaria, Cuba, Democratic Republic of Congo (Zaire), Finland, France, Greece, Japan, Republic of Congo (Brazzaville), Russia and the USA [1].

X-Ray Powder Diffraction[4]
d spacing 3.05 2.65 1.87 1.60 1.32 1.21 1.08 1.02
relative intensity 10 1 7 4 1 2 2 1


References

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References

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  1. ^ American Mineralogist (1984) 69:943-947
  2. ^ webmineral.com/data/Germanite.shtml Webmineral
  3. ^ U.S. Geological Survey (2008). "Germanium—Statistics and Information". U.S. Geological Survey, Mineral Commodity Summaries. http://minerals.usgs.gov/minerals/pubs/commodity/germanium/.
  4. ^ Dana's New Mineralogy, 8th edition. Gaines et al. Wiley
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