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Brassite

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Formula:
Mg(HAsO
 
4
) · 4H
 
2
O
System:OrthorhombicColour:White
Name:Named by François Fontan, Marcel Orliac, François Permingeat, Roland Pierrot, and Réjane Stahl in 1973 for Réjane Brasse, apparently the maiden name of Réjane Stahl, French chemist of Universite de Paris Sud, who first synthesized the compound.


May occur also as a dehydration product of rösslerite.

Classification of Brassite

IMA status:Approved
Strunz 8th edition ID:7/C.15-10
Nickel-Strunz 10th (pending) edition ID:8.CE.15

8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
E : With only medium-sized cations, RO4:H2O about 1:2.5
Dana 8th edition ID:39.1.7.1

39 : HYDRATED ACID PHOSPHATES,ARSENATES AND VANADATES
1 : A[HXO4]·xH2O
Hey's CIM Ref.:20.2.2

20 : Arsenates (also arsenates with phosphate, but without other anions)
2 : Arsenates of Be, Mg, Ca or Ba
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Type Occurrence of Brassite

Type Locality:Jáchymov (St Joachimsthal), Jáchymov (St Joachimsthal) District, Krušné Hory Mts (Erzgebirge), Karlovy Vary Region, Bohemia (Böhmen; Boehmen), Czech Republic
Year of Discovery:1973
Geological Setting of type material:Post-mine alteration of arsenic ore.
Associated Minerals at type locality:
WeiliteArsenicPicropharmacoliteRauenthalite

Physical Properties of Brassite

Lustre:Waxy, Silky, Dull, Earthy
Diaphaneity (Transparency):Translucent
Comment:May have a fine satin-like appearance.
Colour:White
Streak:White
Comment:Soft fine-grained mineral. True hardness unknown.
Tenacity:Brittle
Cleavage:Perfect
{001} perfect.
Fracture:Irregular/Uneven, Splintery
Density (measured):2.28 - 2.33 g/cm3
Density (calculated):2.326 g/cm3
Comment:AC B 32:1460 (1976) structure.

Crystallography of Brassite

Crystal System:Orthorhombic
Class (H-M):mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:Pbca {P21/b 21/c 21/a}
Space Group Setting:Pbca
Cell Parameters:a = 7.472Å, b = 10.891Å, c = 16.585Å
Ratio:a:b:c = 0.686 : 1 : 1.523
Unit Cell Volume:V 1,349.65 ų (Calculated from Unit Cell)
Z:8
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data:
Data courtesy of RRUFF project at University of Arizona, used with permission.
X-Ray Powder Diffraction:
d-spacingIntensity
5.55 (80)
5.45 (80)
4.95 (100)
4.52 (80)
3.98 (80)
3.73 (80)
3.30 (80)
3.08 (100)
Comments:ICDD 23-1228 (synthetic), also 29-860 (calculated pattern).

Optical Data of Brassite

Type:Biaxial (+)
RI values: nα = 1.531 nβ = 1.546 nγ = 1.562
Birefringence:0.031
Maximum Birefringence:δ = 0.031

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Low
Dispersion:r < v moderate
Optical Extinction:XYZ=bac; 2V=very large
Pleochroism:Non-pleochroic

Chemical Properties of Brassite

Formula:
Mg(HAsO
 
4
) · 4H
 
2
O
Essential elements:As, H, Mg, O
All elements listed in formula:As, H, Mg, O

Relationship of Brassite to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
8.CE.05Chudobaite
(Mg,Zn)
 
5
(AsO
 
4
)
 
2
(HAsO
 
4
)
 
2
· 10H
 
2
O
8.CE.05Geigerite
Mn
2+
5
(AsO
 
4
)
 
2
(HAsO
 
4
)
 
2
· 10H
 
2
O
8.CE.10Newberyite
Mg(HPO
 
4
) · 3H
 
2
O
8.CE.20Phosphorrösslerite
Mg(HPO
 
4
) · 7H
 
2
O
8.CE.20Rösslerite
Mg(HAsO
 
4
) · 7H
 
2
O
8.CE.25Metaswitzerite
Mn
 
3
(PO
 
4
)
 
2
· 4H
 
2
O
8.CE.25Switzerite
(Mn,Fe)
 
3
(PO
 
4
)
 
2
· 7H
 
2
O
8.CE.30Lindackerite
CuCu
 
4
(AsO
 
4
)
 
2
(HAsO
 
4
)
 
2
· 8-9H
 
2
O
8.CE.30Ondrušite
CaCu
 
4
(AsO
 
4
)
 
2
(HAsO
 
4
)
 
2
· 10H
 
2
O
8.CE.30Veselovskýite
ZnCu
 
4
(AsO
 
4
)
 
2
(HAsO
 
4
)
 
2
· 9H
 
2
O
8.CE.30Pradetite
CoCu
 
4
(AsO
 
4
)
 
2
(HAsO
 
4
)
 
2
· 9H
 
2
O
8.CE.30Klajite
MnCu
 
4
(AsO
 
4
)
 
2
(HAsO
 
4
)
 
2
· 9-10H
 
2
O
8.CE.35Bobierrite
Mg
 
3
(PO
 
4
)
 
2
· 8H
 
2
O
8.CE.40Annabergite
Ni
 
3
(AsO
 
4
)
 
2
· 8H
 
2
O
8.CE.40Arupite
Ni
 
3
(PO
 
4
)
 
2
· 8H
 
2
O
8.CE.40Barićite
(Mg,Fe)
 
3
(PO
 
4
)
 
2
· 8H
 
2
O
8.CE.40Erythrite
Co
 
3
(AsO
 
4
)
 
2
· 8H
 
2
O
8.CE.40Ferrisymplesite
Fe
3+
3
(AsO
 
4
)
 
2
(OH)
 
3
· 5H
 
2
O
8.CE.40Hörnesite
Mg
 
3
(AsO
 
4
)
 
2
· 8H
 
2
O
8.CE.40Köttigite
Zn
 
3
(AsO
 
4
)
 
2
· 8H
 
2
O
8.CE.40Manganohörnesite
(Mn,Mg)
 
3
(AsO
 
4
)
 
2
· 8H
 
2
O
8.CE.40Parasymplesite
Fe
2+
3
(AsO
 
4
)
 
2
· 8H
 
2
O
8.CE.40Vivianite
Fe
2+
3
(PO
 
4
)
 
2
· 8H
 
2
O
8.CE.40Pakhomovskyite
Co
 
3
(PO
 
4
)
 
2
· 8H
 
2
O
8.CE.45Symplesite
Fe
2+
3
(AsO
 
4
)
 
2
· 8H
 
2
O
8.CE.50Cattiite
Mg
 
3
(PO
 
4
)
 
2
· 22H
 
2
O
8.CE.55Koninckite
Fe
3+
 
PO
 
4
· 3H
 
2
O
8.CE.60Kaňkite
FeAsO
 
4
· 3.5H
 
2
O
8.CE.65Steigerite
Al(VO
 
4
) · 3H
 
2
O
8.CE.70Metaschoderite
Al
 
2
(PO
 
4
)(VO
 
4
) · 6H
 
2
O
8.CE.70Schoderite
Al
 
2
(PO
 
4
)(VO
 
4
) · 8H
 
2
O
8.CE.75Malhmoodite
FeZr(PO
 
4
)
 
2
· 4H
 
2
O
8.CE.75Zigrasite
MgZr(PO
 
4
)
 
2
· 4H
 
2
O
8.CE.75Unnamed (Ca-analogue of Zigrasite)
CaZr[PO
 
4
]
 
2
· 4H
 
2
O
8.CE.80Santabarbaraite
Fe
3+
3
(PO
 
4
)
 
2
(OH)
 
3
· 5H
 
2
O
8.CE.85Metaköttigite
(Zn,Fe,Fe)
 
3
(AsO
 
4
)
 
2
· 8(H
 
2
O,OH)
Related Minerals - Hey's Index Grouping:

- +
20.2.1Bearsite
Be
 
2
(AsO
 
4
)(OH) · 4H
 
2
O
20.2.3Rösslerite
Mg(HAsO
 
4
) · 7H
 
2
O
20.2.4Hörnesite
Mg
 
3
(AsO
 
4
)
 
2
· 8H
 
2
O
20.2.5Weilite
Ca(HAsO
 
4
)
20.2.6Johnbaumite
Ca
 
5
(AsO
 
4
)
 
3
OH
20.2.7Haidingerite
CaHAsO
 
4
· H
 
2
O
20.2.8Pharmacolite
Ca(HAsO
 
4
) · 2H
 
2
O
20.2.9Sainfeldite
CaCa
 
2
Ca
 
2
(AsO
 
4
)
 
2
(HAsO
 
4
)
 
2
· 4H
 
2
O
20.2.10Vladimirite
Ca
 
4
(AsO
 
4
)
 
2
(AsO
 
3
OH) · 4H
 
2
O
20.2.11Guérinite
Ca
 
5
(AsO
 
4
)
 
2
(HAsO
 
4
)
 
2
· 9H
 
2
O
20.2.12Ferrarisite
Ca
 
5
(AsO
 
4
)
 
2
(HAsO
 
4
)
 
2
· 9H
 
2
O
20.2.13Rauenthalite
Ca
 
3
(AsO
 
4
)
 
2
· 10H
 
2
O
20.2.14Phaunouxite
Ca
 
3
(AsO
 
4
)
 
2
· 11H
 
2
O
20.2.15Mcnearite
NaCa
 
5
(AsO
 
4
)(HAsO
 
4
)
 
4
· 4H
 
2
O
20.2.16Bergslagite
CaBeAsO
 
4
(OH)
20.2.17Adelite
CaMg(AsO
 
4
)(OH)
20.2.18Talmessite
Ca
 
2
Mg(AsO
 
4
)
 
2
· 2H
 
2
O
20.2.19Irhtemite
Ca
 
4
Mg(AsO
 
4
)
 
2
(HAsO
 
4
)
 
2
· 4H
 
2
O
20.2.20Camgasite
CaMg(AsO
 
4
)(OH) · 5H
 
2
O
20.2.21Picropharmacolite
Ca
 
4
Mg(AsO
 
4
)
 
2
(HAsO
 
4
)
 
2
· 11H
 
2
O
20.2.22Bariopharmacosiderite
Ba
 
0.5
Fe
3+
4
(AsO
 
4
)
 
3
(OH)
 
4
· 5H
 
2
O

Other Names for Brassite

Synonyms:
IMA1973-047
Other Languages:
German:Brassit
Russian:Брассит
Spanish:Brassita

Other Information

Fluorescence in UV light:Not fluorescent.
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 Brassite

Reference List:

- +
Bull. Min. (1973) 96:365
American Mineralogist (1975): 60: 945.

Acta Crystallographica (1976): B32: 1460-1466, structure.

Internet Links for Brassite

Search Engines:
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  • Look for Brassite images on Google
  • External Links:
  • Look for Brassite on Webmineral
  • Look for Brassite on Athena Mineralogy
  • Look for Brassite on Wikipedia
  • Look for Brassite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Brassite details from Handbook of Mineralogy (PDF)
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  • Localities for Brassite

    (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.
    Czech Republic
     
    • Bohemia (Böhmen; Boehmen)
      • Karlovy Vary Region
        • Krušné Hory Mts (Erzgebirge)
          • Jáchymov (St Joachimsthal) District
    Bull.Soc.fr.Min.Crist.(1974) 96, 365-370
    France
     
    • Languedoc-Roussillon
      • Aude
        • Carcassonne
          • Mas-Cabardès
            • Salsigne
    Le Règne Minéral, Hors série (3), 36-54
    G. Favreau : "La mine d'or de Salsigne : Les minéraux des scories de Villagnère", Le Règne Minéral, hors série, 3, 55-60, 1997
    Germany
     
    • Hesse
      • Richelsdorf District
        • Bauhaus
    Weiss: "Mineralfundstellen, Deutschland West", Weise (Munich), 1990
        • Süss
          • Richelsdorf Smelter
    S. Weiß: "Mineralfundstellen, Deutschland West", Weise (Munich), 1992
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