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Brownmillerite

Big Photo

Ettringer Bellerberg Mt., Ettringen, Mayen, Eifel Mts, Rhineland-Palatinate, Germany
© Leon Hupperichs

Formula:
Ca
 
2
(Al,Fe
3+
 
)
 
2
O
 
5
System:Orthorhombic
Name:The artificial compound was named in 1932 for Dr. Lorrin Thomas Brownmiller (b. 1902), Chief Chemist of the Alpha Portland Cement Company, Easton, Pennsylvania, USA. The name was then transferred to the naturally-occurring mineral.
This page provides mineralogical data about Brownmillerite.

Classification of Brownmillerite

IMA status:Approved
Strunz 8th edition ID:4/A.07-10
Nickel-Strunz 10th (pending) edition ID:4.AC.10

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
A : Metal: Oxygen = 2:1 and 1:1
C : M:O = 1:1 (and up to 1:1.25); with large cations (+- smaller ones)
Dana 8th edition ID:7.11.2.1

7 : MULTIPLE OXIDES
11 : Miscellaneous
Hey's CIM Ref.:7.20.15

7 : Oxides and Hydroxides
20 : Oxides of Fe
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Type Occurrence of Brownmillerite

Type Locality:Ettringer Bellerberg Mt., Ettringen, Mayen, Eifel Mts, Rhineland-Palatinate, Germany
Place of Conservation of Type Material:Mineral Museum, University of Cologne, Cologne, Germany (No. M5026/86)
National Museum of Natural History, Washington, D.C., USA (No. 120045)
Year of Discovery:1964
Geological Setting of type material:In thermally metamorphosed limestone blocks included in volcanic rocks
Associated Minerals at type locality:
WollastoniteSpinelPyrrhotitePortlanditeMayenite
LarniteJenniteJasmunditeGrossularGehlenite
EttringiteDiopsideCalciteAfwillite

Occurrences of Brownmillerite

Geological Setting:In thermally metamorphosed limestones

Crystallography of Brownmillerite

Crystal System:Orthorhombic
Cell Parameters:a = 5.57Å, b = 14.52Å, c = 5.34Å
Ratio:a:b:c = 0.384 : 1 : 0.368
Unit Cell Volume:V 431.88 ų (Calculated from Unit Cell)

Optical Data of Brownmillerite

Type:Biaxial (-)
RI values: nα = 1.960 nβ = 2.010 nγ = 2.040
2V:Measured: 75° , Calculated: 72°
Maximum Birefringence:δ = 0.080

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Very High
Dispersion:strong

Chemical Properties of Brownmillerite

Formula:
Ca
 
2
(Al,Fe
3+
 
)
 
2
O
 
5
Essential elements:Al, Ca, Fe, O
All elements listed in formula:Al, Ca, Fe, O

Relationship of Brownmillerite to other Species

Related Minerals - Nickel-Strunz Grouping):
4.AC.05Swedenborgite
NaBe
 
4
SbO
 
7
4.AC.10Srebrodolskite
Ca
 
2
Fe
 
2
O
 
5
4.AC.15Montroydite
HgO
4.AC.20Litharge
PbO
4.AC.20Romarchite
SnO
4.AC.25Massicot
PbO
Related Minerals - Hey's Index Grouping:
7.20.1Wüstite
FeO
7.20.2Magnetite
Fe
2+
 
Fe
3+
2
O
 
4
7.20.3Maghemite
Fe
 
2
O
 
3
7.20.4Hematite
Fe
 
2
O
 
3
7.20.5Goethite
α-Fe
3+
 
O(OH)
7.20.6Akaganeite
β-Fe
3+
 
O(OH,Cl)
7.20.7Feroxyhyte
Fe
3+
 
O(OH)
7.20.8Lepidocrocite
γ-Fe
3+
 
O(OH)
7.20.9Ferrihydrite
Fe
 
5
O
 
3
(OH)
 
9
7.20.10Amakinite
(Fe
2+
 
,Mg)(OH)
 
2
7.20.11Magnesioferrite
MgFe
3+
2
O
 
4
7.20.12Muskoxite
Mg
 
7
Fe
 
4
O
 
13
·10H
 
2
O
7.20.13Srebrodolskite
Ca
 
2
Fe
 
2
O
 
5
7.20.14Hercynite
FeAl
 
2
O
 
4

Other Names for Brownmillerite

Synonyms:
CeliteIMA1963-017
German names:
BrownmilleritCelit
Russian names:
Браунмиллерит
Spanish names:
BrownmilleritaCelita

Other Information

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 Brownmillerite

Reference List:Hentschel, G., (1964): Mayenit, 12CaO 7Al2O3, und Brownmillerit, 2CaO.(Al,Fe)2O3, zwei neue Minerale in den Kalksteineinschlüssen der Lava des Ettringer Bellerberges: Neues Jahrb. Mineral., Mh. 1964, 22-29.

American Mineralogist: 50: 2106.

Acta Crystallographica: B27: 2311-2315.

Internet Links for Brownmillerite

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  • Raman and XRD data at RRUFF project
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    Localities for Brownmillerite

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    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
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    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Austria
     
    • Styria
      • Bad Radkersburg
        • Klöch
    		R. Exel: Die Mineralien und Erzlagerstätten Österreichs (1993)
    China
     
    • Xinjiang (Xinjiang-Uygur) Autonomous Region
      • Hami (Kumul; Qumul) Prefecture
        • Hami (Kumul; Qumul) Co.
          • Huangshan-Jing'erquan ore belt
    		Jingwen Mao, Pirajno, F., Zuoheng Zang, Fengmei Chai, Hua Wu, Shiping Chen, Linsong Cheng, Jianmin Yang, and Changqing Zhang (2007): Journal of Asian Earth Sciences (in press).
    Germany
     
    • Rhineland-Palatinate
      • Eifel Mts
        • Daun
          • Üdersdorf
    		Schüller, W., Betz, V., Die Mineralien vom Emmelberg, Lapis 12/1986
        • Mayen
          • Ettringen
    		[Hentschel, G., Mayenit, 12CaO . 7 Al2O3, und Brownmillerit, 2CaO.(Al,Fe)2O3, zwei neue Minerale in den Kalksteineinschlüssen der Lava des Ettringer Bellerberges , N. Jb. Mineral., Mh., 22-29, 1964
    Israel
     
    Gross, S. (1977): The Mineralogy of the Hatrurim Formation, Israel. Geological Survey of Israel, Bulletin no. 70, 80 pp.
    Mineral and/or Locality
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