Kegelite
Appearance
Kegelite | |
---|---|
![]() Kegelite microcrystals with a 1 cm. siderite crystal at right, from the type locality | |
General | |
Category | Phyllosilicates |
Formula (repeating unit) | Pb8Al4Si8O20(SO4)2(CO3)4(OH)8 |
Strunz classification | 9.EC.80 |
Dana classification | 71.05.01.01 |
Crystal system | Monoclinic Unknown space group |
Identification | |
Color | Colorless to white |
Crystal habit | Pseudohexagonal plates in spherical aggregates |
Cleavage | Perfect on {100} |
Tenacity | Extremely flexible |
Mohs scale hardness | no data |
Luster | Vitreous |
Streak | White |
Diaphaneity | Transparent to translucent |
Specific gravity | 4.5 |
Optical properties | Biaxial (-) |
Refractive index | n = 1.81 parallel to {100} |
References | [1][2][3] |
Kegelite is a complex silicate mineral with formula Pb8Al4Si8O20(SO4)2(CO3)4(OH)8.
It was first described in 1975 for an occurrence in the Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia and named for Friedrich Wilhelm Kegel (?-1948), Director of mining operations at Tsumeb.[1][3] It occurs in a deeply oxidized polymetallic ore deposits in Tsumeb. Associated minerals include quartz, galena, mimetite, hematite, leadhillite, anglesite, fleischerite, melanotekite and alamosite.[1] It has also been reported from the Zeehan district in Tasmania and from Tune, Sarpsberg, Østfold, Norway.[3]
References
- ^ a b c http://rruff.geo.arizona.edu/doclib/hom/kegelite.pdf Handbook of Mineralogy
- ^ http://www.webmineral.com/data/Kegelite.shtml Webmineral data
- ^ a b c http://www.mindat.org/min-2175.html Mindat.org
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