Kegelite
| Kegelite | |
|---|---|
|
Kegelite microcrystals with a 1 cm. siderite crystal at right, from the type locality | |
| General | |
| Category | Silicate mineral |
| Formula (repeating unit) | Pb8Al4Si8O20(SO4)2(CO3)4(OH)8 |
| Strunz classification | 09.EC.80 Phyllosilicates |
| Dana classification | 71.05.01.01 |
| Identification | |
| Color | Colorless to white |
| Crystal habit | Pseudohexagonal plates in spherical aggregates |
| Crystal system | Monoclinic Space group: A2/m,A2,Am |
| Cleavage | Perfect on {100} |
| Tenacity | Extremely °exible |
| 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
- 1 2 3 http://rruff.geo.arizona.edu/doclib/hom/kegelite.pdf Handbook of Mineralogy
- ↑ http://www.webmineral.com/data/Kegelite.shtml Webmineral data
- 1 2 3 http://www.mindat.org/min-2175.html Mindat.org
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