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Braunite

A valid IMA mineral species - grandfathered

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Braunite

N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

Braunite, etc.

Caspar quarry, Ettringen, Vordereifel, Mayen-Koblenz, Rhineland-Palatinate, Germany

Braunite

Wessels Mine, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

Braunite

N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

Braunite, etc.

Caspar quarry, Ettringen, Vordereifel, Mayen-Koblenz, Rhineland-Palatinate, Germany

Braunite

Wessels Mine, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

Braunite

N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa

Braunite, etc.

Caspar quarry, Ettringen, Vordereifel, Mayen-Koblenz, Rhineland-Palatinate, Germany

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About BrauniteHide

Formula:

Mn²⁺Mn³⁺₆(SiO₄)O₈

Colour:

Brownish black, steel-grey

Lustre:

Sub-Metallic

Hardness:

6 - 6½

Specific Gravity:

4.72 - 4.83

Crystal System:

Tetragonal

Member of:

Braunite Group

Name:

After Wilhelm von Braun (* 1. October 1790 in Thal (Ruhla); † 6. February 1872 in Gotha), official and minister in Gotha, Germany, supporter of geology and mineralogy. He supplied the original material for the description of braunite.

Co-Type Localities:

ⓘ Friedrichroda, Gotha District, Thuringia, Germany
ⓘ Elgersburg, Ilm District, Thuringia, Germany
ⓘ Oehrenstock, Langewiesen, Ilmenau, Ilm District, Thuringia, Germany
ⓘ Praborna Mine, Servette-Chuc mining complex, Saint-Marcel, Aosta Valley, Italy

The Mn²⁺ analogue of neltnerite.

Compare also braunite-II.

Unique IdentifiersHide

Mindat ID:

757

Long-form identifier:

mindat:1:1:757:7

Similar NamesHide

Barneite	A rock subtype
Barronite	A valid IMA mineral species	(◻_0.5Ba_0.5)(UO₂)₂Si₅O₁₂(OH) · 2H₂O
Beraunite	A valid IMA mineral species - grandfathered	Fe₆³⁺(PO₄)₄O(OH)₄ · 6H₂O
Birunite	A valid IMA mineral species - grandfathered - questionable	Ca₁₈(SiO₃)_8.5(CO₃)_8.5SO₄ · 15H₂O(?)
Bornite	A valid IMA mineral species - grandfathered	Cu₅FeS₄
Bornite (of Pinkerton)	A rock subtype
Braunite-II	Valid as an unnamed mineral	Ca(Mn³⁺,Fe)₁₄(SiO₄)O₂₀
Brianite	A valid IMA mineral species	Na₂CaMg(PO₄)₂
Browneite	A valid IMA mineral species	MnS

IMA Classification of BrauniteHide

IMA status:

Approved, 'Grandfathered' (first described prior to 1959)

IMA Formula:

Mn²⁺Mn³⁺₆SiO₁₂

Classification of BrauniteHide

Strunz-mindat (2026):

9.AG.05

9 : SILICATES (Germanates)
A : Nesosilicates
G : Nesosilicates with additional anions; cations in > [6] +- [6] coordination

Dana 8th ed.:

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

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.

Symbol	Source	Reference for Standard
Bnt	IMA–CNMNC	Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43
Bnt	The Canadian Mineralogist (2019)	The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download

Physical Properties of BrauniteHide

Lustre:

Sub-Metallic

Transparency:

Opaque

Colour:

Brownish black, steel-grey

Streak:

Black

Hardness:

6 - 6½ on Mohs scale

Hardness:

VHN₁₀₀=920 - 1079 kg/mm² - Vickers

Tenacity:

Brittle

Cleavage:

Perfect
{112} perfect.

Fracture:

Irregular/Uneven, Sub-Conchoidal

Density:

4.72 - 4.83 g/cm³ (Measured) 4.86 g/cm³ (Calculated)

Optical Data of BrauniteHide

Anisotropism:

Weak in air, distinct in oil - dark to lighter slate gray.

Reflectivity:

Wavelength	R₁ (%)	R₂ (%)
400nm	23.4%	25.4%
420nm	22.7%	24.5%
440nm	22.0%	23.6%
460nm	21.5%	22.9%
480nm	21.0%	22.4%
500nm	20.5%	21.9%
520nm	20.0%	21.5%
540nm	19.6%	21.2%
560nm	19.3%	20.9%
580nm	19.0%	20.6%
600nm	18.8%	20.3%
620nm	18.6%	20.0%
640nm	18.5%	19.8%
660nm	18.3%	19.6%
680nm	18.2%	19.5%
700nm	18.1%	19.4%

Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 25.4%.
R₁ shown in black, R₂ shown in red

Colour in reflected light:

Grayish white with a brownish tinge.

Chemistry of BrauniteHide

Mindat Formula:

Mn²⁺Mn³⁺₆(SiO₄)O₈

Element Weights:

Element	% weight
Mn	63.602 %
O	31.753 %
Si	4.645 %

Calculated from ideal end-member formula.

Elements listed:

Mn, O, Si - search for minerals with similar chemistry

Common Impurities:

Fe,Ca,B,Ba,Ti,Al,Mg

Crystallography of BrauniteHide

Crystal System:

Tetragonal

Class (H-M):

4/mmm(4/m2/m2/m) - Ditetragonal Dipyramidal

Space Group:

I4₁/acd

Cell Parameters:

a = 9.432 Å, c = 18.703 Å

Ratio:

a:c = 1 : 1.983

Unit Cell V:

1,663.87 Å³ (Calculated from Unit Cell)

Morphology:

Pyramidal {011} and {131}; pseudo-octahedral. 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}.

Comment:

Cell from de Villiers (1975). Cell dimensions variable: a = 9.36-9.45, c = 18.60-18.97 Å.

Crystallographic forms of BrauniteHide

Crystal Atlas:

Image Loading

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Braunite no.9 - {112} - Goldschmidt (1913-1926)

Braunite no.20 - {112} - Goldschmidt (1913-1926)

Braunite no.23 - {112} - Goldschmidt (1913-1926)

3d models and HTML5 code kindly provided by www.smorf.nl.

Crystal StructureHide

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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure

ID	Species	Reference	Year	Locality	Pressure (GPa)	Temp (K)
0000788	Braunite	de Villiers J P R (1980) The crystal structure of braunite II and its relation to bixbyite and braunite American Mineralogist 65 756-765	1980	Wessels mine, near Hotazel, South Africa	0	293
0008124	Braunite	Miletich R, Allan D R, Angel R J (1998) Structural control of polyhedral compression in synthetic braunite, Mn2+Mn3+6O8SiO4 Physics and Chemistry of Minerals 25 183-192	1998		0.0001	293
0008123	Braunite	Miletich R, Allan D R, Angel R J (1998) Structural control of polyhedral compression in synthetic braunite, Mn2+Mn3+6O8SiO4 Physics and Chemistry of Minerals 25 183-192	1998		0.0001	293
0000543	Braunite	Moore P B, Araki T (1976) Braunite: its structure and relationship to bixbyite, and some insights on the genealogy of fluorite derivative structures American Mineralogist 61 1226-1240	1976		0	293
0000484	Braunite	de Villiers J P R (1975) The crystal structure of braunite with reference to its solid-solution behavior American Mineralogist 60 1098-1104	1975		0	293
0008125	Braunite	Miletich R, Allan D R, Angel R J (1998) Structural control of polyhedral compression in synthetic braunite, Mn2+Mn3+6O8SiO4 Physics and Chemistry of Minerals 25 183-192	1998		1.38	293
0008126	Braunite	Miletich R, Allan D R, Angel R J (1998) Structural control of polyhedral compression in synthetic braunite, Mn2+Mn3+6O8SiO4 Physics and Chemistry of Minerals 25 183-192	1998		2.66	293
0008127	Braunite	Miletich R, Allan D R, Angel R J (1998) Structural control of polyhedral compression in synthetic braunite, Mn2+Mn3+6O8SiO4 Physics and Chemistry of Minerals 25 183-192	1998		4.51	293
0008128	Braunite	Miletich R, Allan D R, Angel R J (1998) Structural control of polyhedral compression in synthetic braunite, Mn2+Mn3+6O8SiO4 Physics and Chemistry of Minerals 25 183-192	1998		5.63	293
0008129	Braunite	Miletich R, Allan D R, Angel R J (1998) Structural control of polyhedral compression in synthetic braunite, Mn2+Mn3+6O8SiO4 Physics and Chemistry of Minerals 25 183-192	1998		7.69	293

CIF Raw Data - click here to close

data_global
_chemical_name_mineral 'Braunite'
loop_
_publ_author_name
'de Villiers J P R'
_journal_name_full 'American Mineralogist'
_journal_volume 65 
_journal_year 1980
_journal_page_first 756
_journal_page_last 765
_publ_section_title
;
 The crystal structure of braunite II and its relation to bixbyite and braunite
;
_database_code_amcsd 0000788
_chemical_compound_source 'Wessels mine, near Hotazel, South Africa'
_chemical_formula_sum 'Ca (Mn11.62 Fe2.38) Si O24'
_cell_length_a 9.431
_cell_length_b 9.431
_cell_length_c 37.774
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 3359.761
_exptl_crystal_density_diffrn      4.837
_symmetry_space_group_name_H-M 'I 41/a c d'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,1/2+z'
  '1/4-y,3/4-x,3/4+z'
  '3/4-y,1/4-x,1/4+z'
  '1/4+y,3/4+x,3/4-z'
  '3/4+y,1/4+x,1/4-z'
  '1/4+y,3/4-x,1/4-z'
  '3/4+y,1/4-x,3/4-z'
  '1/4-y,3/4+x,1/4+z'
  '3/4-y,1/4+x,3/4+z'
  '1/2+x,-y,z'
  '+x,1/2-y,1/2+z'
  '1/2-x,y,-z'
  '-x,1/2+y,1/2-z'
  '1/2+x,y,1/2-z'
  '+x,1/2+y,-z'
  '1/2-x,-y,1/2+z'
  '-x,1/2-y,+z'
  '1/4+y,1/4+x,1/4+z'
  '3/4+y,3/4+x,3/4+z'
  '1/4-y,1/4-x,1/4-z'
  '3/4-y,3/4-x,3/4-z'
  '1/4-y,1/4+x,3/4-z'
  '3/4-y,3/4+x,1/4-z'
  '1/4+y,1/4-x,3/4+z'
  '3/4+y,3/4-x,1/4+z'
  '-x,y,1/2+z'
  '1/2-x,1/2+y,+z'
  'x,-y,1/2-z'
  '1/2+x,1/2-y,-z'
  '-x,-y,-z'
  '1/2-x,1/2-y,1/2-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Ca   0.00000   0.25000   0.12500   1.00000
Mn1   0.00000   0.25000  -0.00918   0.83000
Fe1   0.00000   0.25000  -0.00918   0.17000
Mn2   0.20970   0.00000   0.25000   0.83000
Fe2   0.20970   0.00000   0.25000   0.17000
Mn3   0.24080   0.49080   0.12500   0.83000
Fe3   0.24080   0.49080   0.12500   0.17000
Mn4   0.03120   0.00060   0.06290   0.83000
Fe4   0.03120   0.00060   0.06290   0.17000
Mn5  -0.00960   0.00440   0.18772   0.83000
Fe5  -0.00960   0.00440   0.18772   0.17000
Si   0.00000   0.25000   0.37500   1.00000
O1   0.11970   0.17150   0.02560   1.00000
O2   0.33140   0.40100   0.03110   1.00000
O3   0.39820   0.12270   0.04120   1.00000
O4   0.11780   0.40710   0.08970   1.00000
O5   0.17010   0.11210   0.09090   1.00000
O6   0.38740   0.33610   0.10040   1.00000
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Ca 0.00440 0.00440 0.00550 -0.00030 0.00000 0.00000
Mn1 0.00740 0.01030 0.00630 0.00290 0.00000 0.00000
Fe1 0.00740 0.01030 0.00630 0.00290 0.00000 0.00000
Mn2 0.00630 0.00940 0.00740 0.00000 0.00000 0.00250
Fe2 0.00630 0.00940 0.00740 0.00000 0.00000 0.00250
Mn3 0.00730 0.00730 0.00630 0.00010 -0.00050 0.00050
Fe3 0.00730 0.00730 0.00630 0.00010 -0.00050 0.00050
Mn4 0.00570 0.00690 0.00770 0.00070 0.00050 -0.00170
Fe4 0.00570 0.00690 0.00770 0.00070 0.00050 -0.00170
Mn5 0.00460 0.00600 0.00620 -0.00060 -0.00020 -0.00020
Fe5 0.00460 0.00600 0.00620 -0.00060 -0.00020 -0.00020
Si 0.00490 0.00490 0.00570 0.00000 0.00000 0.00000
O1 0.01080 0.01060 0.00670 0.00300 -0.00110 0.00080
O2 0.00710 0.00760 0.00660 -0.00070 0.00120 0.00130
O3 0.00370 0.00970 0.01120 -0.00070 0.00190 0.00440
O4 0.00570 0.00570 0.00610 -0.00130 -0.00220 0.00280
O5 0.00670 0.00830 0.00520 0.00060 -0.00120 0.00210
O6 0.00770 0.00950 0.00640 0.00010 -0.00030 -0.00030

X-Ray Powder DiffractionHide

Loading XRD data...

2θ (degrees) d-spacing (Å)

Data courtesy of RRUFF project at University of Arizona, used with permission.

Powder Diffraction Data:

d-spacing	Intensity
2.72 Å	(100)
1.656 Å	(70)
2.14 Å	(50)
2.35 Å	(40)
1.420 Å	(40)
1.074 Å	(40)
3.49 Å	(30)

Geological EnvironmentHide

Paragenetic Mode(s):

Paragenetic Mode	Earliest Age (Ga)
High-𝑇 alteration and/or metamorphism
32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits
Stage 7: Great Oxidation Event	<2.4
47e : [Vanadates, chromates, manganates]
47h : [Near-surface oxidized, dehydrated minerals]

Geological Setting:

Metamorphism of manganese silicates and weathering product.

Type Occurrence of BrauniteHide

Co-Type Localities:

Synonyms of BrauniteHide

Brachytypous Manganese-Ore

Braunite-I

Braunite (of Haidinger)

Heteroclase

Heteroclin

Leptonematite (of Adam)

Marceline

Pesillite

Other Language Names for BrauniteHide

Dutch:Brauniet

German:Braunit
Braunit-I
Hartbraunstein
Heteroklin
Pesillit

Japanese:ブラウン鉱

Russian:Браунит

Simplified Chinese:褐锰矿

Spanish:Braunita
Pesillita

Relationship of Braunite to other SpeciesHide

Member of:

Braunite Group

Other Members of Braunite Group:

Abswurmbachite	CuMn³⁺₆(SiO₄)O₈	Tet. 4/mmm(4/m2/m2/m) : I4₁/acd
'Braunite-II'	Ca(Mn³⁺,Fe)₁₄(SiO₄)O₂₀	Tet. 4/mmm(4/m2/m2/m) : I4₁/acd
Gatedalite	ZrMn²⁺₂Mn³⁺₄SiO₁₂	Tet. 4/mmm(4/m2/m2/m) : I4₁/acd
Neltnerite	CaMn³⁺₆(SiO₄)O₈	Tet. 4/mmm(4/m2/m2/m) : I4₁/acd
Skogbyite	Zr(Mg₂Mn³⁺₄)SiO₁₂	Tet. 4/mmm(4/m2/m2/m) : I4₁/acd

Common AssociatesHide

Associations Based on Photo Data:

85 photos of Braunite associated with Calcite	CaCO₃
45 photos of Braunite associated with Pyrolusite	Mn⁴⁺O₂
44 photos of Braunite associated with Quartz	SiO₂
29 photos of Braunite associated with Hausmannite	Mn²⁺Mn³⁺₂O₄
27 photos of Braunite associated with Baryte	BaSO₄
23 photos of Braunite associated with Piemontite	(CaCa)(AlAlMn³⁺)O[Si₂O₇][SiO₄](OH)
21 photos of Braunite associated with Andradite	Ca₃Fe³⁺₂(SiO₄)₃
17 photos of Braunite associated with Rhodonite	CaMn₃Mn[Si₅O₁₅]
14 photos of Braunite associated with Namansilite	NaMn³⁺Si₂O₆
11 photos of Braunite associated with Macfallite	Ca₂Mn³⁺₃(SiO₄)(Si₂O₇)(OH)₃

Related Minerals - Strunz-mindat Grouping Hide

9.AG.	Aluminotaipingite-(CeCa)	(Ce₆Ca₃)◻Al(SiO₄)₃[SiO₃(OH)]₄F₃	Trig. 3m : R3c
9.AG.	'Ivanyukite-Na-T'	Na₂Ti₄(SiO₄)₃(OH)O₃ · 7H₂O	Trig. 3m : R3m
9.AG.	'Ivanyukite-Na-C'	Na₂Ti₄(SiO₄)₃(OH)₂O₂ · 6H₂O	Iso. 43m : P43m
9.AG.	Edgrewite	Ca₉(SiO₄)₄F₂	Mon. 2/m : P2₁/c
9.AG.02

Braunite

About BrauniteHide

Unique IdentifiersHide

Similar NamesHide

IMA Classification of BrauniteHide

Classification of BrauniteHide

Mineral SymbolsHide

Physical Properties of BrauniteHide

Optical Data of BrauniteHide

Chemistry of BrauniteHide

Crystallography of BrauniteHide

Crystallographic forms of BrauniteHide

Crystal StructureHide

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Type Occurrence of BrauniteHide

Synonyms of BrauniteHide

Other Language Names for BrauniteHide

Relationship of Braunite to other SpeciesHide

Common AssociatesHide

Related Minerals - Strunz-mindat GroupingHide

Related Minerals - Strunz-mindat Grouping Hide