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Braunite

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Formula:
Mn
2+
 
Mn
3+
6
(SiO
 
4
)O
 
8
System:TetragonalColour:Brownish black, ...
Hardness:6 - 6½
Member of:Braunite Group
Name:After Wilhelm von Braun (1790-1872), official and minister in Gotha, Germany, supporter of geology and mineralogy. He supplied the original material for the description of braunite.


Then Mn2+ analogue of neltnerite.

Classification of Braunite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:8/B.09-03
Nickel-Strunz 10th (pending) edition ID:9.AG.05

9 : SILICATES (Germanates)
A : Nesosilicates
G : Nesosilicates with additional anions; cations in > [6] +- [6] coordination
Dana 8th edition ID:7.5.1.3

7 : MULTIPLE OXIDES
5 : (AB)2X3
Hey's CIM Ref.:14.17.3

14 : Silicates not Containing Aluminum
17 : Silicates of Mn
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Type Occurrence of Braunite

Co-type Localities:Friedrichroda, Thuringian Forest, Thuringia, Germany
Elgersburg, Ilmenau District, Thuringian Forest, Thuringia, Germany
Oehrenstock (Öhrenstock), Langewiesen, Ilmenau District, Thuringian Forest, Thuringia, Germany
Prabornaz Mine (Praborna Mine), Saint-Marcel, Aosta Valley, Italy
Year of Discovery:1827

Occurrences of Braunite

Geological Setting:Metamorphism of manganese silicates and weathering product.

Physical Properties of Braunite

Lustre:Sub-Metallic
Diaphaneity (Transparency):Opaque
Colour:Brownish black, steel-grey
Streak:Black
Hardness (Mohs):6 - 6½
Hardness (Vickers):VHN100=920 - 1079 kg/mm2
Tenacity:Brittle
Cleavage:Perfect
{112} perfect.
Fracture:Irregular/Uneven, Sub-Conchoidal
Density (measured):4.72 - 4.83 g/cm3
Density (calculated):4.86 g/cm3

Crystallography of Braunite

Crystal System:Tetragonal
Class (H-M):4/mmm (4/m 2/m 2/m) - Ditetragonal Dipyramidal
Space Group:I41/acd
Cell Parameters:a = 9.41(4) Å, c = 18.8(2) Å
Ratio:a:c = 1 : 1.998
Unit Cell Volume:V 1,664.70 ų (Calculated from Unit Cell)
Z:8
Morphology:Pyramidal {011} and {131}. Striated on {001} and {201} parallel to [010] Granular massive.
Twinning:On {112} producing a combination with only a small reentrant angle (0°18') on е{011}.
Crystal Atlas:
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Braunite no.9 - Goldschmidt (1913-1926)
Braunite no.20 - Goldschmidt (1913-1926)
Braunite no.23 - Goldschmidt (1913-1926)

About Crystal Atlas

The mindat.org Crystal Atlas allows you to view a selection of crystal drawings of real and idealised crystal forms for this mineral and, in certain cases, 3d rotating crystal objects. The 3d models and HTML5 code are kindly provided by www.smorf.nl.

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X-Ray Powder Diffraction:
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Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Optical Data of Braunite

Type:Anisotropic
Anisotropism:Weak in air, distinct in oil - dark to lighter slate gray.
Colour in reflected light:Grayish white with a brownish tinge.

Chemical Properties of Braunite

Formula:
Mn
2+
 
Mn
3+
6
(SiO
 
4
)O
 
8
Simplified for copy/paste:Mn2+Mn3+6(SiO4)O8
Essential elements:Mn, O, Si
All elements listed in formula:Mn, O, Si
Common Impurities:Fe,Ca,B,Ba,Ti,Al,Mg

Relationship of Braunite to other Species

Member of:Braunite Group
Other Members of Group:

- +
Abswurmbachite
CuMn
3+
6
(SiO
 
4
)O
 
8
Gatedalite
ZrMn
2+
2
Mn
3+
4
SiO
 
12
Neltnerite
CaMn
3+
6
(SiO
 
4
)O
 
8
Related Minerals - Nickel-Strunz Grouping):

- +
9.AG.05Abswurmbachite
CuMn
3+
6
(SiO
 
4
)O
 
8
9.AG.05Neltnerite
CaMn
3+
6
(SiO
 
4
)O
 
8
9.AG.05Braunite-II
CaMn
3+
14
(SiO
 
4
)O
 
20
9.AG.10Långbanite
(Mn
2+
 
,Ca)
 
4
(Mn
3+
 
,Fe
3+
 
)
 
9
Sb
5+
 
(SiO
 
4
)
 
2
O
 
16
9.AG.15Malayaite
CaSn(SiO
 
4
)O
9.AG.15Titanite
CaTi(SiO
 
4
)O
9.AG.15Vanadomalayaite
CaV
4+
 
(SiO
 
4
)O
9.AG.15Natrotitanite
(Na
 
0.5
Y
 
0.5
)Ti(SiO
 
4
)O
9.AG.20Cerite-(Ce)
(Ce,Ca)
 
9
(Mg,Fe)(SiO
 
4
)
 
3
(HSiO
 
4
)
 
4
(OH)
 
3
9.AG.20Cerite-(La)
(La,Ce,Ca)
 
9
(Fe,Ca,Mg)(SiO
 
4
)
 
3
(HSiO
 
4
)
 
4
(OH)
 
3
9.AG.20Aluminocerite-(Ce)
(Ce,La,Ca)
 
9
(Al,Fe
3+
 
)(SiO
 
4
)
 
3
(HSiO
 
4
)
 
4
(OH)
 
3
9.AG.25Trimounsite-(Y)
Y
 
2
Ti
 
2
(SiO
 
4
)O
 
5
9.AG.25Yftisite-(Y)
(Y,Dy,Er)
 
4
(Ti,Sn)(SiO
 
4
)
 
2
O(F,OH)
 
6
9.AG.30Sitinakite
KNa
 
2
Ti
 
4
(SiO
 
4
)
 
2
O
 
5
(OH) · 4H
 
2
O
9.AG.35Kittatinnyite
Ca
 
2
Mn
 
2
Mn(SiO
 
4
)
 
2
(OH)
 
4
· 9H
 
2
O
9.AG.40aNatisite
Na
 
2
Ti(SiO
 
4
)O
9.AG.40bParanatisite
Na
 
2
Ti(SiO
 
4
)O
9.AG.45Törnebohmite-(Ce)
(Ce,La)
 
2
Al(SiO
 
4
)
 
2
(OH)
9.AG.45Törnebohmite-(La)
(La,Ce)
 
2
Al(SiO
 
4
)
 
2
(OH)
9.AG.50Kuliokite-(Y)
Y
 
4
Al(SiO
 
4
)
 
2
(OH)
 
2
F
 
5
9.AG.55Chantalite
CaAl
 
2
(SiO
 
4
)(OH)
 
4
9.AG.60Mozartite
CaMn
3+
 
(SiO
 
4
)(OH)
9.AG.60Vuagnatite
CaAl(SiO
 
4
)(OH)
9.AG.65Hatrurite
Ca
 
3
(SiO
 
4
)O
9.AG.70Jasmundite
Ca
 
11
(SiO
 
4
)
 
4
O
 
2
S
9.AG.75Afwillite
Ca
 
3
(HSiO
 
4
)
 
2
· 2H
 
2
O
9.AG.80Bultfonteinite
Ca
 
2
(HSiO
 
4
)F · H
 
2
O
9.AG.85Zoltaiite
BaV
4+
2
V
3+
12
(SiO
 
4
)
 
2
O
 
19
9.AG.90Tranquillityite
(Fe
2+
 
,Ca)
 
8
(Zr,Y)
 
2
Ti
 
3
(SiO
 
4
)
 
3
O
 
4
Related Minerals - Hey's Index Grouping:

- +
14.17.1Rhodonite
MnSiO
 
3
14.17.2Tephroite
Mn
2+
2
SiO
 
4
14.17.4Alleghanyite
Mn
2+
5
(SiO
 
4
)
 
2
(OH)
 
2
14.17.5Ribbeite
(Mn
2+
 
,Mg)
 
5
(SiO
 
4
)
 
2
(OH)
 
2
14.17.6Leucophoenicite
Mn
2+
7
(SiO
 
4
)
 
3
(OH)
 
2
14.17.7Jerrygibbsite
Mn
2+
9
(SiO
 
4
)
 
4
(OH)
 
2
14.17.8Bementite
Mn
 
7
Si
 
6
O
 
15
(OH)
 
8
14.17.9Parsettensite
K
 
1.2
Mn
 
8
(Si,Al)
 
12
O
 
26
(OH)
 
10
14.17.10Yofortierite
Mn
 
5
Si
 
8
O
 
20
(OH)
 
2
· 8-9H
 
2
O

Other Names for Braunite

Synonyms:
Brachytypous Manganese-OreBraunite-IBraunite (of Haidinger)HeteroclaseHeteroclin
Leptonematite (of Adam)MarcelinePesillite
Other Languages:
German:Braunit
Hartbraunstein
Heteroklin
Pesillit
Japanese:ブラウン鉱
Russian:Браунит
Simplified Chinese:褐锰矿
Spanish:Braunita
Pesillita

Other Information

Other Information:Weakly magnetic.
Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Braunite

Reference List:

- +
Haidinger, W. (1827): On the crystalline Forms and Properties of the Manganese Ores.- Edinburgh Journal of Science, IV, 41

Haidinger, W. (1828): Mineralogische Beschreibung der Manganerze. I. Prismatoïdisches Manganerz, Manganit. II. Pyramidales Manganerz, Hausmannit. III. Untheilbares Manganerz, Psilomelan. IV. Brachytypes Manganerz, Braunit. V. Prismatisches Manganerz, Pyrolusit.- Poggendorffs Annalen der Physik und Chemie 14, 197-211

Turner, E. (1831): Chemical Examination of the Oxides of Manganese.- Transactions of the Royal Society of Edinburgh, Vol. II, 143-174

Breithaupt in Evreinov (1840), Ann. Phys.: 49: 204.

Switzer (1938), American Mineralogist: 23: 649.

Palache, Charles, Harry Berman & Clifford Frondel (1944), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Volume I: Elements, Sulfides, Sulfosalts, Oxides. John Wiley and Sons, Inc., New York. 7th edition, revised and enlarged: 551-554.

American Mineralogist (1976): 61: 1226-1240.

Robie, R.A., Huebner, J.S., and Hemingway, B.S. (1995) Heat capacities and thermodynamic properties of braunite (Mn7SiO12) and rhodonite (MnSiO3). American Mineralogist: 80: 560-575.

Bevan, D.J.M. & R.L.Martin, The role of the coordination defect: A new structural description of four fluorite-related sesquioxide minerals, bixbyite, braunite, braunite II, parwelite, and their structural relationships. Journal of Solid State Chemistry 181,2250-2259(2008)

Internet Links for Braunite

Search Engines:
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  • External Links:
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  • Look for Braunite on Wikipedia
  • Look for Braunite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Braunite details from Handbook of Mineralogy (PDF)
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  • Specimens:The following Braunite specimens are currently listed for sale on minfind.com.

    Localities for Braunite

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