Itinga, Minas Gerais, Brazil
Al2SiO4O
Crystal System: orthorhombic
Colour: pink to red brown, occasionally yellow, green, white, gray, rarely violet
Lustre: vitreous, sub-vitreous, greasy
Habitus: prismatic
Hardness: 6½ - 7½
Fracture: irregular/uneven, sub-conchoidal
Cleavage: good on {110} - poor on {100}
Density: 3.149 g/cm3
Origin and geological occurrence: andalusite is the result of contact metamorphism of argillaceous sediments; also in regionally metamorphosed schists. Rarely found in granites and pegmatites. It is a polymorph of Al2SiO4O.
Samples:
9A.7 Andalusite #neso soro silicates |