Help mindat.org|Log In|Register|
Home PageMindat NewsThe Mindat ManualHistory of MindatCopyright StatusManagement TeamContact UsAdvertise on Mindat
Donate to MindatSponsor a PageSponsored PagesTop Available PagesMindat AdvertisersAdvertise on MindatThe Mindat Store
Minerals by PropertiesMinerals by ChemistryRandom MineralSearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
StatisticsThe ElementsMember ListBooks & MagazinesMineral Shows & EventsThe Mindat DirectoryHow to Link to MindatDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Braunite

This page is currently not sponsored. Click here to sponsor this page.
Formula:
Mn2+Mn63+SiO12
System:
Tetragonal
Colour:
Brownish black, ...
Lustre:
Sub-Metallic
Hardness:
6 - 6½
Member of:
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

Approved, 'Grandfathered' (first described prior to 1959)
9.AG.05

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
14.17.3

14 : Silicates not Containing Aluminum
17 : Silicates of Mn

Physical Properties of Braunite

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

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

IMA Formula:
Mn2+Mn63+SiO12
Elements listed in formula:
Common Impurities:
Fe,Ca,B,Ba,Ti,Al,Mg

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}.

Crystallographic forms of Braunite

Crystal Atlas:
Image Loading
Click on an icon to view
Braunite no.9 - Goldschmidt (1913-1926)
Braunite no.20 - Goldschmidt (1913-1926)
Braunite no.23 - Goldschmidt (1913-1926)
3d models and HTML5 code kindly provided by www.smorf.nl.

Toggle
Edge Lines | Miller Indicies | Axes

Transparency
Opaque | Translucent | Transparent

View
Along a-axis | Along b-axis | Along c-axis | Start rotation | Stop rotation
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Occurrences of Braunite

Type Occurrence of Braunite

Relationship of Braunite to other Species

Member of:
Other Members of Group:
AbswurmbachiteCuMn63+(SiO4)O8
GatedaliteZrMn22+Mn43+SiO12
NeltneriteCaMn63+(SiO4)O8
9.AG.05AbswurmbachiteCu2+Mn63+O8(SiO4)
9.AG.05NeltneriteCaMn63+O8(SiO4)
9.AG.05Braunite-IICaMn143+(SiO4)O20
9.AG.10LångbaniteMn42+Mn93+Sb5+O16(SiO4)2
9.AG.15MalayaiteCaSnO(SiO4)
9.AG.15TitaniteCaTiSiO5
9.AG.15VanadomalayaiteCaVO(SiO4)
9.AG.15Natrotitanite(Na0.5Y0.5)Ti(SiO4)O
9.AG.15ŻabińskiiteCa[Al0.5(Ta,Nb)0.5](SiO4)O
9.AG.20Cerite-(Ce)(Ce,La,Ca)9(Mg,Fe3+)(SiO4)3(SiO3OH)4(OH)3
9.AG.20Cerite-(La)(La,Ce,Ca)9(Fe3+,Ca,Mg)(SiO4)3(SiO3OH)4(OH)3
9.AG.20Aluminocerite-(Ce)(Ce,Ca)9Al(SiO4)3(SiO3OH)4(OH)3
9.AG.25Trimounsite-(Y)Y2Ti2O5SiO4
9.AG.25Yftisite-(Y)(Y,Dy,Er)4(Ti,Sn)(SiO4)2O(F,OH)6
9.AG.25Mieite-(Y)Y4Ti(SiO4)2O[F,(OH)]6
9.AG.30SitinakiteKNa2Ti4Si2O13(OH) · 4H2O
9.AG.35KittatinnyiteCa2(Mn2+,Mn3+)3Si2O8(OH)4 · 9H2O
9.AG.40aNatisiteNa2TiO(SiO4)
9.AG.40bParanatisiteNa2TiO(SiO4)
9.AG.45Törnebohmite-(Ce)Ce2Al(SiO4)2(OH)
9.AG.45Törnebohmite-(La)La2Al(SiO4)2(OH)
9.AG.50Kuliokite-(Y)Y4Al(SiO4)2(OH)2F5
9.AG.55ChantaliteCaAl2SiO4(OH)4
9.AG.60MozartiteCaMn3+SiO4(OH)
9.AG.60VuagnatiteCaAlSiO4(OH)
9.AG.65HatruriteCa3SiO5
9.AG.70JasmunditeCa11O2(SiO4)4S
9.AG.75AfwilliteCa3(SiO4)(SiO2(OH)2) · 2H2O
9.AG.80BultfonteiniteCa2[SiO3(OH)]F · H2O
9.AG.85ZoltaiiteBaV24+V123+Si2O27
9.AG.90TranquillityiteFe82+Ti3Zr2Si3O24
14.17.1RhodoniteMn2+SiO3
14.17.2TephroiteMn22+SiO4
14.17.4AlleghanyiteMn52+(SiO4)2(OH)2
14.17.5RibbeiteMn52+(SiO4)2(OH)2
14.17.6LeucophoeniciteMn72+(SiO4)3(OH)2
14.17.7JerrygibbsiteMn92+(SiO4)4(OH)2
14.17.8BementiteMn7Si6O15(OH)8
14.17.9Parsettensite(K,Na,Ca)7.5(Mn,Mg)49Si72O168(OH)50 · nH2O
14.17.10Yofortierite(Mn2+,Mg,Fe3+)5Si8O20(OH,H2O)2 · 7H2O

Other Names for Braunite

Name in Other Languages:

Other Information

Other Information:
Weakly magnetic.
Health Risks:
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.

Gutzmer, J. and Beukes, N. J. (1997): Mineralogy and mineral chemistry of oxide-facies manganese ores of the Postmasburg manganese field, South Africa. Mineralogical Magazine, 61, 213-232. [on stacking model for the braunite group]

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

mindat.org URL:
https://www.mindat.org/min-757.html
Please feel free to link to this page.
Specimens:
The following Braunite specimens are currently listed for sale on minfind.com.

Localities for Braunite

Mineral and/or Locality  
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2017, except where stated. Mindat.org relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: June 23, 2017 07:52:31 Page generated: June 17, 2017 16:02:09
Go to top of page