Braunite-II Mineral Data (original) (raw)

General Braunite-II Information

Help on Chemical Formula: Chemical Formula:

Mn++Mn+++6SiO12

Help on Composition: Composition:

Molecular Weight = 604.64 gm

Manganese 63.60 % Mn 11.73 % MnO / 78.33 % Mn2O3

Silicon 4.64 % Si 9.94 % SiO2

Oxygen 31.75 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Help on Empirical Formula: Empirical Formula:

Mn2+Mn3+6SiO12

Help on Environment: Environment:

Manganese oxide mineral deposits. Metamorphic and secondary weathering environments

Help on IMA Status: IMA Status:

Not Approved IMA 1967

Help on Locality: Locality:

Metamorphic, hydrothermal, and sedimentary rocks. Link to MinDat.org Location Data.

Help on Name Origin: Name Origin:

Named after K. Braun (1790-1872) from Gotha, Germany.

Help on Name Pronunciation: Name Pronunciation:

Braunite-II Say BRAUNITE-II

Braunite-II Image

Click Here for Larger Braunite-II Image in a New Browser Window Images:

Click Here for Larger Braunite-II Image Braunite-II Braunite-I Comments: Crystals of braunite. Location: Black Rock Mine, Kalahari Manganese Field, Northern Cape Province, South Africa.Scale: Crystal size 1.3 cm. © John Veevaert

Braunite-II Crystallography

Help on Axial Ratios: Axial Ratios:

a:c = 1:1.9904

Help on Cell Dimensions: Cell Dimensions:

a = 9.38, c = 18.67, Z = 8; V = 1,642.67 Den(Calc)= 4.89

Help on Crystal System: Crystal System:

Tetragonal - Ditetragonal DipyramidalH-M Symbol (4/m 2/m 2/m) Space Group: I 41/acd

Help on X Ray Diffraction: X Ray Diffraction:

By Intensity(I/Io): 2.72(1), 1.656(0.7), 2.14(0.5),

Help on Forms: Forms:

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Physical Properties of Braunite-II

Help on Cleavage: Cleavage:

{111} Perfect

Help on Color: Color:

Grayish black, Brownish gray, Dark brownish black.

Help on Density: Density:

4.72 - 4.82, Average = 4.76

Help on Diaphaneity: Diaphaneity:

Opaque

Help on Fracture: Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Help on Habit: Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Help on Hardness: Hardness:

6-6.5 - Orthoclase-Pyrite

Help on Luster: Luster:

Sub Metallic

Help on Magnetism: Magnetism:

Nonmagnetic

Help on Streak: Streak:

brownish gray black

Optical Properties of Braunite-II

Help on Optical Data: Optical Data:

NCalc= 2.37 - from Gladstone-Dale relationship (KC = 0.2796) where Ncalc=Dcalc*KC+1
NCalc= 2.33 - from Gladstone-Dale relationship (KC = 0.2796) where Ncalc=Dmeas*KC+1

Calculated Properties of Braunite-II

Help on Electron Density: Electron Density:

Bulk Density (Electron Density)=4.61 gm/cc
note: Specific Gravity of Braunite-II =4.89 gm/cc.

Help on Fermion Index: Fermion Index:

Fermion Index = 0.0023216105
Boson Index = 0.9976783895

Help on Photoelectric: Photoelectric:

PEBraunite-II = 16.86 barns/electron
U=PEBraunite-II x rElectron Density= 77.73 barns/cc.

Help on Radioactivity: Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Braunite-II is Not Radioactive

Braunite-II Classification

Help on Dana Class: Dana Class:

07.05.01.03 (07)Multiple Oxides

(07.05)where A B X2

(07.05.01)Humite group (Tetragonal: I41/acd) containing Si

07.05.01.01 Braunite-I MnMn6SiO12 I 41/acd 4/m 2/m 2/m

07.05.01.02 Neltnerite CaMn6SiO12 I 41/acd 4/m 2/m 2/m

07.05.01.03 Braunite-II* MnMn6SiO12 I 41/acd 4/m 2/m 2/m

07.05.01.04 Abswurmbachite CuMn6SiO12 I 41/acd 4/m 2/m 2/m

Help on Strunz Class: Strunz Class:

09.AG.05 09 - SILICATES (Germanates)

09.A - Nesosilicates

09.AG -Nesosilicates with additional anions; cations in > [6] � [6] coordination

09.AG.05 Abswurmbachite CuMn6SiO12 I 41/acd 4/m 2/m 2/m

09.AG.05 Braunite-I MnMn6SiO12 I 41/acd 4/m 2/m 2/m

09.AG.05 Braunite-II* MnMn6SiO12 I 41/acd 4/m 2/m 2/m

09.AG.05 Neltnerite CaMn6SiO12 I 41/acd 4/m 2/m 2/m

Other Braunite-II Information

Help on References: References:

NAME( Duda&Rejl90) PHYS. PROP.(Bull.Miner.,Vol.107-111,1984-1988)

Help on See Also: See Also:

Links to other databases for Braunite-II :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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Ask about Braunite-II here :
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Print or Cut-and-Paste your Braunite-II Specimen Label here :

Braunite-II

Mn++Mn+++6SiO12
Dana No: 07.05.01.03 Strunz No: 09.AG.05
Locality:

Notes: