Mineralogy Database

Brownmillerite Mineral Data

Search Webmineral :

General Brownmillerite Information

Help on Chemical  Formula: Chemical Formula: Ca2(Al,Fe+++)2O5
Help on Composition: Composition: Molecular Weight = 240.09 gm
   Calcium   33.39 %  Ca   46.71 % CaO
   Aluminum  12.36 %  Al   23.36 % Al2O3
   Iron      20.93 %  Fe   26.93 % FeO
   Oxygen    33.32 %  O
            ______        ______ 
            100.00 %       97.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Ca2Al1.1Fe2+0.9O5
Help on Environment: Environment: Thermally metamorphosed limestone blocks included in volcanic rocks.
Help on IMA Status: IMA Status: Approved IMA 1964
Help on Locality: Locality: Ettringer-Bellerberg volcano, near Mayen, Eifel district, Germay. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Lorrin Thomas Brownmiller (1902-), Chef chemist of the Alpha Portland Cement Company, Easton, Pennsylvania, USA.
Help on Name Pronunciation: Name Pronunciation: Brownmillerite + Pronunciation Say BROWNMILLERITE
Help on Synonym: Synonym: ICSD 9197
  PDF 30-226

Brownmillerite Image

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


Comments: Brownish-orange masses of brownmillerite in skarn.
Location: Bellerberg, Ettringen, Eifel Mountains, Rheinland-Pfalz, Germany. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

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

  Reinhardbraunsite   Brownmillerite

Comments: Pink crystalline reinhardbraunsite in brownmillerite.
Location: Near Bellerberg, Eifel, Rheinland-Pflaz, Germany. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Brownmillerite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.3822:1:0.3698
Help on Cell Dimensions: Cell Dimensions: a = 5.52, b = 14.44, c = 5.34, Z = 4; V = 425.64 Den(Calc)= 3.75
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Ibmm
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.65(1), 2.78(0.5), 7.19(0.5),

Physical Properties of Brownmillerite

Help on Color: Color: Reddish brown.
Help on Density: Density: 3.76
Help on Diaphaneity: Diaphaneity: Semitransparent
Help on Habit: Habit: Platy - Sheet forms (e.g. micas).
Help on Habit: Habit: Square - Occurs as square crystals in shape or outline.
Help on Streak: Streak: light brown

Optical Properties of Brownmillerite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.354 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.358 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2676,KPDmeas= 0.2668,KC= 0.1971
Ncalc = 1.74
Help on Optical Data: Optical Data: Biaxial (-), a=1.96, b=2.01, g=2.04, bire=0.0800, 2V(Calc)=72, 2V(Meas)=75.
Help on Pleochroism (x): Pleochroism (x): yellow brown.
Help on Pleochroism (y): Pleochroism (y): yellow brown.
Help on Pleochroism (z): Pleochroism (z): dark brown.

Calculated Properties of Brownmillerite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.69 gm/cc
note: Specific Gravity of Brownmillerite =3.76 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0050487097
Boson Index = 0.9949512903
Help on Photoelectric: Photoelectric: PEBrownmillerite = 10.73 barns/electron
U=PEBrownmillerite x rElectron Density= 39.57 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Brownmillerite is Not Radioactive

Brownmillerite Classification

Help on  Dana Class: Dana Class: (07)Multiple Oxides
  (07.11)as titano-oxides with [4] and [6] substitutions
  (07.11.02)Dana Group Brownmillerite Ca2(Al,Fe)2O5 Ibmm 2/m 2/m 2/m Srebrodolskite Ca2Fe2O5 P nma 2/m 2/m 2/m
Help on  Strunz Class: Strunz Class: 04.AC.10 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate
  04.A - Metal:Oxygen = 2.1 and 1:1
  04.AC -M:O = 1:1 (and up to 1:1.25); with large cations (� smaller ones)
04.AC.10 Brownmillerite Ca2(Al,Fe)2O5 Ibmm 2/m 2/m 2/m
04.AC.10 Srebrodolskite Ca2Fe2O5 P nma 2/m 2/m 2/m

Other Brownmillerite Information

Help on References: References: NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
Help on See Also: See Also: Links to other databases for Brownmillerite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

Search for Brownmillerite using:

Web webmineral.com
[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Brownmillerite :

Ask about Brownmillerite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

Print or Cut-and-Paste your Brownmillerite Specimen Label here :


Dana No: Strunz No: 04.AC.10





Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.