Cabalzarite

Cabalzarite is a rare arsenate mineral with the chemical formula Ca(Mg,Al,Fe3+
)
2
[AsO
4
]
2
•2(H
2
O,OH)
. It is a member of the tsumcorite group. It crystallizes in the monoclinic system and typically occurs as clusters of crystals or granular aggregates.[1][2]

Cabalzarite
Cabalzarite found in Switzerland
General
CategoryArsenate minerals
Formula
(repeating unit)
Ca(Mg,Al,Fe3+
)
2
[AsO
4
]
2
•2(H
2
O,OH)
Strunz classification8.CG.15
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupC2/m
Unit cella = 8.925 Å,
b = 6.143 Å,
c = 7.352 Å,
β = 115.25°; Z = 2
Identification
ColorLight brown, brownish pink, orange brown
Crystal habitAggregates and clusters, granular
FractureIrregular
Mohs scale hardness5
LusterVitreous
StreakWhite
Diaphaneitytransparent
Specific gravity3.89
Optical propertiesBiaxial
Refractive indexnα = 1.700 nγ = 1.760
Birefringenceδ = 0.060
References[1][2][3]

It was first described for samples from an abandoned manganese mine in Falotta, Graubünden, Switzerland and named for Swiss amateur mineralogist Walter Cabalzar. It was approved as a new mineral by the IMA in 1997. It has also been reported from the Aghbar mine in Ouarzazate Province, Morocco.[2]

References

  1. Cabalzarite mineral data from Webmineral
  2. Cabalzarite mineral information on Mindat.org
  3. Brugger J., Meisser N., Schenk K., Berlepsch P., Bonin M., Armbruster T., Nyfeler D. and Schmidt S. 2000: Description and crystal structure of cabalzarite Ca(Mg,Fe,Al)2(AsO4)2(H2O,OH)2, a new mineral from the tsumcorite group. American Mineralogist, 85(9), 1307-1314;
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