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:

MonoclinicSpace 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 :

A Bijoux Google Search for Kegelite
Adam's Minerals Google Search for Kegelite
Cape Minerals Google Search for Kegelite
Dakota Matrix Minerals Google Search for Kegelite
Excalibur Mineral Corp. Google Search for Kegelite
Exceptional Minerals Google Search for Kegelite
John Betts Fine Minerals Search for Kegelite
McDougall Minerals Google Search for Kegelite
Mineral News Website Link
Rock and Mineral Shows Google Search for Kegelite
Weinrich Minerals, Inc. Google Search 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: