Braunite-II
Valid as an unnamed mineral
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About Braunite-II
Formula:
Ca(Mn3+,Fe)14(SiO4)O20
Mn:Fe ratio is approx. 5:1.
Colour:
black
Lustre:
Sub-Metallic
Hardness:
6
Crystal System:
Tetragonal
Member of:
Name:
For the close relation to braunite.
Has a doubled unit-cell parameter c by comparison to braunite.
"The structure of braunite II, (...), is simply an intergrowth of slabs of bixbyite- and braunite-type structures, linked by the CaO8 cubes of the latter." (Bevan and Martin, 2008).
"The structure of braunite II, (...), is simply an intergrowth of slabs of bixbyite- and braunite-type structures, linked by the CaO8 cubes of the latter." (Bevan and Martin, 2008).
Unique Identifiers
Mindat ID:
4860
Long-form identifier:
mindat:1:1:4860:2
Similar Names
IMA Classification of Braunite-II
IMA status notes:
Unnamed (probably valid)
Approval history:
Unnamed, but probably valid.
Classification of Braunite-II
9.AG.05
9 : SILICATES (Germanates)
A : Nesosilicates
G : Nesosilicates with additional anions; cations in > [6] +- [6] coordination
9 : SILICATES (Germanates)
A : Nesosilicates
G : Nesosilicates with additional anions; cations in > [6] +- [6] coordination
7.5.1.3
7 : MULTIPLE OXIDES
5 : (AB)2X3
7 : MULTIPLE OXIDES
5 : (AB)2X3
Physical Properties of Braunite-II
Sub-Metallic
Colour:
Black
Comment:
yellow-brown in reflected light
Hardness:
6 on Mohs scale
Hardness Data:
Measured
Chemistry of Braunite-II
Mindat Formula:
Ca(Mn3+,Fe)14(SiO4)O20
Mn:Fe ratio is approx. 5:1.
Mn:Fe ratio is approx. 5:1.
Element Weights:
Crystallography of Braunite-II
Crystal System:
Tetragonal
Class (H-M):
4/mmm(4/m2/m2/m) - Ditetragonal Dipyramidal
Space Group:
I41/acd
Cell Parameters:
a = 9.431 Å, c = 37.774 Å
Ratio:
a:c = 1 : 4.005
Unit Cell V:
3359.76 ų
Z:
8
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.68 Å | (40) |
| 2.72 Å | (100) |
| 2.35 Å | (60) |
| 1.996 Å | (20) |
| 1.666 Å | (90) |
| 1.423 Å | (70) |
| 1.081 Å | (30) |
| 1.052 Å | (20) |
First Recorded Occurrence of Braunite-II
Synonyms of Braunite-II
Other Language Names for Braunite-II
German:Braunit-II
Relationship of Braunite-II to other Species
Member of:
Other Members of Braunite Group:
| Abswurmbachite | CuMn3+6(SiO4)O8 | Tet. 4/mmm(4/m2/m2/m) : I41/acd |
| Braunite | Mn2+Mn3+6(SiO4)O8 | 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 Associates
Associations Based on Photo Data:
| 16 photos of Braunite-II associated with Andradite | Ca3Fe3+2(SiO4)3 |
| 9 photos of Braunite-II associated with Hausmannite | Mn2+Mn3+2O4 |
| 3 photos of Braunite-II associated with Calcite | CaCO3 |
| 2 photos of Braunite-II associated with Pectolite | NaCa2Si3O8(OH) |
| 2 photos of Braunite-II associated with Namansilite | NaMn3+Si2O6 |
| 2 photos of Braunite-II associated with Hematite | Fe2O3 |
| 2 photos of Braunite-II associated with Despujolsite | Ca3Mn4+(SO4)2(OH)6 · 3H2O |
| 2 photos of Braunite-II associated with Clinochlore | Mg5Al(AlSi3O10)(OH)8 |
| 2 photos of Braunite-II associated with Baryte | BaSO4 |
| 2 photos of Braunite-II associated with Taniajacoite | SrCaMn3+2Si4O11(OH)4 · 2H2O |
Related Minerals - Strunz-mindat Grouping
| 9.AG. | Aluminotaipingite-(CeCa) | (Ce6Ca3)◻Al(SiO4)3[SiO3(OH)]4F3 |
| 9.AG. | 'Ivanyukite-Na-T' | Na2Ti4(SiO4)3(OH)O3 · 7H2O |
| 9.AG. | 'Ivanyukite-Na-C' | Na2Ti4(SiO4)3(OH)2O2 · 6H2O |
| 9.AG. | Edgrewite | Ca9(SiO4)4F2 |
| 9.AG.02 | Gatedalite | ZrMn2+2Mn3+4SiO12 |
| 9.AG.05 | Abswurmbachite | CuMn3+6(SiO4)O8 |
| 9.AG.05 | Neltnerite | CaMn3+6(SiO4)O8 |
| 9.AG.05 | Skogbyite | Zr(Mg2Mn3+4)SiO12 |
| 9.AG.05 | Braunite | Mn2+Mn3+6(SiO4)O8 |
| 9.AG.10 | Långbanite | Mn2+4Mn3+9Sb5+O16(SiO4)2 |
| 9.AG.12 | Taipingite-(CeCa) | (Ce7Ca2)◻Mg(SiO4)3[SiO3(OH)]4F3 |
| 9.AG.15 | Żabińskiite | Ca[Al0.5(Ta,Nb)0.5)]O(SiO4) |
| 9.AG.15 | Titanite | CaTiO(SiO4) |
| 9.AG.15 | Vanadomalayaite | CaVO(SiO4) |
| 9.AG.15 | Natrotitanite | (Na0.5Y0.5)TiO(SiO4) |
| 9.AG.15 | Malayaite | CaSnO(SiO4) |
| 9.AG.20 | Ferricerite-(LaCa) | (La6Ca3)◻Fe3+(SiO4)3(SiO3OH)4(OH)3 |
| 9.AG.20 | Aluminocerite-(CeCa) | (Ce6Ca3)◻Al(SiO4)3[SiO3(OH)]4(OH)3 |
| 9.AG.20 | Cerite-(CeCa) | (Ce7Ca2)◻Mg(SiO4)3(SiO3OH)4(OH)3 |
| 9.AG.20 | Nipeiite-(Ce) | Ce9Fe3+(SiO4)6[SiO3(OH)](OH)3 |
| 9.AG.25 | 'Yftisite-(Y)' | (Y,Dy,Er)4(Ti,Sn)(SiO4)2O(F,OH)6 |
| 9.AG.25 | Mieite-(Y) | Y4Ti(SiO4)2O[F,(OH)]6 |
| 9.AG.25 | Trimounsite-(Y) | Y2Ti2(SiO4)O5 |
| 9.AG.30 | Sitinakite | KNa2Ti4(SiO4)2O5(OH) · 4H2O |
| 9.AG.35 | Kittatinnyite | Ca2Mn2Mn(SiO4)2(OH)4 · 9H2O |
| 9.AG.40b | Paranatisite | Na2Ti(SiO4)O |
| 9.AG.40a | Natisite | Na2Ti(SiO4)O |
| 9.AG.45 | Törnebohmite-(Ce) | Ce2Al(SiO4)2(OH) |
| 9.AG.45 | Törnebohmite-(La) | La2Al(SiO4)2(OH) |
| 9.AG.50 | Ivanyukite-Na | Na2Ti4(SiO4)3(OH)2O2 · 6H2O |
| 9.AG.50 | Ivanyukite-K | K2Ti4(SiO4)3(OH)2O2 · 9H2O |
| 9.AG.50 | Ivanyukite-Cu | CuTi4(SiO4)3(OH)2O2 · 7H2O |
| 9.AG.50 | Kuliokite-(Y) | Y4Al(SiO4)2(OH)2F5 |
| 9.AG.50 | Hydroxyledgrewite | Ca9(SiO4)4(OH)2 |
| 9.AG.52 | Ulfanderssonite-(Ce) | (Ce15Ca)Σ16Mg2(SiO4)10(SiO3OH)(OH,F)5Cl3 |
| 9.AG.55 | Chantalite | CaAl2(SiO4)(OH)4 |
| 9.AG.60 | Vuagnatite | CaAl(SiO4)(OH) |
| 9.AG.60 | Mozartite | CaMn3+(SiO4)(OH) |
| 9.AG.65 | Hatrurite | Ca3(SiO4)O |
| 9.AG.70 | Jasmundite | Ca11(SiO4)4O2S |
| 9.AG.75 | Afwillite | Ca3[SiO4][SiO2(OH)2] · 2H2O |
| 9.AG.80 | Bultfonteinite | Ca2(HSiO4)F · H2O |
| 9.AG.85 | Zoltaiite | BaV4+2V3+12(SiO4)2O19 |
| 9.AG.90 | Tranquillityite | (Fe2+,Ca)8(Zr,Y)2Ti3(SiO4)3O12 |
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Braunite-II
mindat.org URL:
https://www.mindat.org/min-4860.html
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Please feel free to link to this page.
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References for Braunite-II
Reference List:
de Villiers, P. R., Herbstein, F. H. (1967) Distinction between two members of the braunite group. American Mineralogist, 52 (1-2) 20-30
Moore, Paul B., Araki, Takaharu (1976) Braunite: its structure and relationship to bixbyite, and some insights on the genealogy of fluorite derivative structures. American Mineralogist, 61 (11-12) 1226-1240
de Villiers, Johan P. R. (1980) The crystal structure of braunite II and its relation to bixbyite and braunite. American Mineralogist, 65 (7-8) 756-765
Baudracco-Gritti, Célestine (1985) Substitution du manganèse bivalent par du calcium dans les minéraux du groupe : braunite, neltnérite, braunite II. Bulletin de Minéralogie, 108 (3) 437-445 doi:10.3406/bulmi.1985.7840[Amer. Mineral. 71 (1986) 1543: abstract and discussion]
de Villiers, Johan P., Buseck, Peter R. (1989) Stacking variations and nonstoichiometry in the bixbyite-braunite polysomatic mineral group. American Mineralogist, 74 (11-12) 1325-1336
Bevan, D. J. M., Martin, R. L. (2008) The role of the coordination defect: A new structural description of four fluorite-related sesquioxide minerals, bixbyite (Mn2O3), braunite (Mn7SiO12), braunite II (CaMn14SiO24), parwelite (Mn10Sb2As2Si2O24), and their structural relationships. Journal of Solid State Chemistry, 181. 2250-2259 doi:10.1016/j.jssc.2008.04.046
Localities for Braunite-II
Showing 4 localities.
Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Morocco | |
| FAVREAU G. & DIETRICH J.E. (2006) |
South Africa (FRL) | |
| de Villiers et al. (1967) +3 other references |
| De Villiers (1945b) +6 other references |
| Beukes et al. (1995) +1 other reference |
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Wessels Mine, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa