Kegelite Mineral Data

General Kegelite Information

Chemical Formula:

Pb8Al4Si8O20(SO4)2(CO3)4(OH)8

Composition:

Molecular Weight = 2,878.42 gm

Aluminum 3.75 % Al 7.08 % Al₂O₃

Silicon 7.81 % Si 16.70 % SiO₂

Hydrogen 0.28 % H 2.50 % H₂O

Lead 57.59 % Pb 62.03 % PbO

Carbon 1.67 % C 6.12 % CO₂

Sulfur 2.23 % S 5.56 % SO₃

Oxygen 26.68 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Pb₈Al₄Si₈(SO₄)₂(CO₃)₄(OH)₈O₂₀

Environment:

Deep oxidation zone at the mine.

IMA Status:

Approved IMA 1975

Locality:

Tsumbe, Namibia. Link to MinDat.org Location Data.

Name Origin:

Named for Friedrich Wilhelm Kegel, director of the Tsumbe mine from 1922 to 1938.

Name Pronunciation:

Kegelite

Kegelite Image

Images:

Kegelite

Comments: Small, transparent pseudo-cubic kegelite crystals.
Location: Tsumbe, Namibia.. Scale: See Image.
© William Pinch

Kegelite Crystallography

Axial Ratios:

a:b:c =1.353:1:0.5778

Cell Dimensions:

a = 21.04, b = 15.55, c = 8.986, Z = 3; beta = 91° V = 2,939.52 Den(Calc)= 4.88

Crystal System:

Monoclinic Space Group: A2/m,A2,Am

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 21(1), 2.591(0.9), 3.82(0.8),

Physical Properties of Kegelite

Cleavage:

{???} Perfect

Color:

Colorless, Pearl white.

Density:

4.46 - 4.549, Average = 4.5

Diaphaneity:

Transparent to Translucent

Luster:

Pearly

Streak:

white

Optical Properties of Kegelite

Gladstone-Dale:

CI meas= -0.102 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.017 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.166,KPDmeas= 0.1798,KC= 0.1632
Ncalc = 1.73 - 1.8

Optical Data:

Biaxial (-), b=1.81

Calculated Properties of Kegelite

Electron Density:

Bulk Density (Electron Density)=4.30 gm/cc
note: Specific Gravity of Kegelite =4.88 gm/cc.

Fermion Index:

Fermion Index = 0.13
Boson Index = 0.87

Photoelectric:

PE_Kegelite=1,004.03 barns/electron
U=PE_Kegelite x rElectron Density=4,316.79 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Kegelite is Not Radioactive

Kegelite Classification

Dana Class:

71.05.01.01 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.05)with other anions

(71.05.01)Dana Group

71.05.01.01 Kegelite Pb8Al4Si8O20(SO4)2(CO3)4(OH)8 A2/m,A2,Am Mono

Strunz Class:

09.EC.80 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EC -Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets

09.EC.80 Kegelite Pb8Al4Si8O20(SO4)2(CO3)4(OH)8 A2/m,A2,Am Mono

Other Kegelite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Kegelite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

Search for Kegelite using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Kegelite :

Ask about Kegelite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

Print or Cut-and-Paste your Kegelite Specimen Label here :

Kegelite

Pb8Al4Si8O20(SO4)2(CO3)4(OH)8
Dana No: 71.05.01.01 Strunz No: 09.EC.80
Locality:

Notes:

Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.