Kegelite

General Information: Chemical Formula:Pb8Al4Si8O20(SO4)2(CO3)4(OH)8 Composition:(Molecular Weight = 2,878.42 gm)Aluminum 3.75 % AlSilicon 7.81 % SiHydrogen 0.28 % H Lead 57.59 % PbCarbon 1.67 % C Sulfur 2.23 % S Oxygen 26.68 % O  Empirical Formula: Pb8Al4Si8(SO4)2(CO3)4(OH)8O20 Environment:Deep oxidation zone at the mine. IMA Status:Approved IMA 1975 Locality:Tsumbe, Namibia. Name Origin:Named for Friedrich Wilhelm Kegel, director of the Tsumbe mine from 1922 to 1938.Physical Properties: Cleavage:[???] Perfect Color:colorless or pearl white. Density:4.46 - 4.549, Average = 4.5 Diaphaniety:Transparent to Translucent Luster:Pearly Streak:whiteMore details...