Mineralogy Database

Congolite Mineral Data

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General Congolite Information

Help on Chemical  Formula: Chemical Formula: (Fe++,Mg,Mn)3B7O13Cl
Help on Composition: Composition: Molecular Weight = 458.00 gm
   Magnesium   4.78 %  Mg    7.92 % MgO
   Manganese   3.60 %  Mn    4.65 % MnO
   Iron       21.95 %  Fe   28.24 % FeO
   Boron      16.52 %  B    53.20 % B2O3
   Chlorine    7.74 %  Cl    7.74 % Cl
                -   %   Cl   -1.75 % -O=Cl2   
   Oxygen     45.41 %  O
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Fe2+1.8Mg0.9Mn2+0.3B7O13Cl
Help on Environment: Environment: Found in insoluble residue from a drill core into sedimentary evaporites.
Help on IMA Status: IMA Status: Approved IMA 1972
Help on Locality: Locality: Brazzaville, Congo. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for the locality.
Help on Synonym: Synonym: ICSD 60504
  PDF 25-2

Congolite Image

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Comments: Pearly crystalline grains of congolite.
Location: Brazzaville, Pool, Congo. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Congolite Crystallography

Help on Axial Ratios: Axial Ratios: a:c = 1:2.44175
Help on Cell Dimensions: Cell Dimensions: a = 8.6225, c = 21.054, Z = 6; V = 1,355.60 Den(Calc)= 3.37
Help on Crystal System: Crystal System: Trigonal - Ditrigonal Pyramidal H-M Symbol (3m) Space Group: R 3c
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.725(1), 3.05(0.8), 2.061(0.75),

Physical Properties of Congolite

Help on Color: Color: Light red.
Help on Density: Density: 3.58
Help on Diaphaneity: Diaphaneity: Transparent
Help on Hardness: Hardness: 6.5-7.5
Help on Luster: Luster: Vitreous (Glassy)

Optical Properties of Congolite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.043 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.016 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2205,KPDmeas= 0.2075,KC= 0.2169
Ncalc = 1.73 - 1.78
Help on Optical Data: Optical Data: Uniaxial (-), e=1.731, w=1.755, bire=0.0240.

Calculated Properties of Congolite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.25 gm/cc
note: Specific Gravity of Congolite =3.37 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.04
Boson Index = 0.96
Help on Photoelectric: Photoelectric: PECongolite = 8.32 barns/electron
U=PECongolite x rElectron Density= 27.06 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Congolite is Not Radioactive

Congolite Classification

Help on  Dana Class: Dana Class: (25)Anhydrous Borates Containing Hydroxyl or Halogen
  (25.06)Dana Type
  (25.06.02)Boracite Group (Trigonal: R3c) Congolite (Fe,Mg,Mn)3B7O13Cl R 3c 3m Trembathite (Mg,Fe)3B7O13Cl R 3c 3m
Help on  Strunz Class: Strunz Class: 06.GA.10 06 - BORATES
  06.G - Heptaborates and other Megaborates
  06.GA -Tekto-heptaborates
06.GA.10 Congolite (Fe,Mg,Mn)3B7O13Cl R 3c 3m
06.GA.10 Trembathite (Mg,Fe)3B7O13Cl R 3c 3m

Other Congolite Information

Help on References: References: NAME( AntBidBlaNic5) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
Help on See Also: See Also: Links to other databases for Congolite :
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

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Dana No: Strunz No: 06.GA.10





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