Kegelite

Kegelite
Kegelite microcrystals with a 1 cm. siderite crystal at right, from the type locality
General
CategoryPhyllosilicates
Formula
(repeating unit)
Pb8Al4Si8O20(SO4)2(CO3)4(OH)8
IMA symbolKeg[1]
Strunz classification9.EC.80
Dana classification71.05.01.01
Crystal systemMonoclinic
Unknown space group
Identification
ColorColorless to white
Crystal habitPseudohexagonal plates in spherical aggregates
CleavagePerfect on {100}
TenacityExtremely flexible
Mohs scale hardnessno data
LusterVitreous
StreakWhite
DiaphaneityTransparent to translucent
Specific gravity4.5
Optical propertiesBiaxial (-)
Refractive indexn = 1.81 parallel to {100}
References[2][3][4]

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.[2][4] It occurs in a deeply oxidized polymetallic ore deposits in Tsumeb. Associated minerals include quartz, galena, mimetite, hematite, leadhillite, anglesite, fleischerite, melanotekite and alamosite.[2] It has also been reported from the Zeehan district in Tasmania and from Tune, Sarpsborg, Østfold, Norway.[4]

References

[edit]
  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ a b c http://rruff.geo.arizona.edu/doclib/hom/kegelite.pdf Handbook of Mineralogy
  3. ^ http://www.webmineral.com/data/Kegelite.shtml Webmineral data
  4. ^ a b c http://www.mindat.org/min-2175.html Mindat.org