Calderite

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calderite
Dark red hexoctahedral crystals on light colored rock
Calderite crystals on matrix from Sunndal Norway
General
CategorySilicate mineral
Formula
(repeating unit)
(Mn2+Ca)3(Fe3+Al)2(SiO4)3
Strunz classification9.AD.25 (10 ed)
8/A.08–40 (8 ed)
Dana classification51.4.3a.6
Crystal systemCubic
Crystal classHexoctahedral (m3m)
H-M symbol: (4/m 3 2/m)
Space groupIa3d
Unit cella = 11.819 Å; Z = 8
Identification
Colorbrownish red to brownish yellow
CleavageNone
Mohs scale hardness6.5-7.5
LusterVitreous
Streakwhite
Diaphaneitytransparent to translucent
Specific gravity3.756
Optical propertiesIsotropic
Refractive indexn = 1.872
References[1][2]

Calderite is a mineral in the garnet group with the chemical formula (Mn2+, Ca)3(Fe3+, Al)2(SiO4)3.

It is dark reddish brown to dark yellowish in color and generally granular massive in form.[3]

It was named for geologist James Calder who worked on the geology of India; the name was first applied to a rock in manganese deposits in Katkamsandi, Hazaribagh district, Bihar and at Netra, Balaghat district, Madhya Pradesh, India. later transferred to its predominant mineral.[2][3] In 1909 it was described as a mineral from Otjosondu, Otjozondjupa Region, Namibia.[1]

See also[edit]

  • James Calder; J. D. Herbert (1981). Geology of the Indian Sub-continent: Observations on Mineralogy, Cypsum, Mines and Mountain Formations (reprint ed.). Cosmo Publications. p. 218.

References[edit]