Synonym: Lapis crucifer; Lapis cruciatur; Cross stone.
Clades:
SilicatesChemical: Al2SiO5.
Region: Georgetown, California.
Color: grey.
Crystal: Orthorhombic.
Used as a gem; as an amulet or souvenir by the pilgrims returning from Santiago de Compostela.
MineralogyChiastolite is a variety of
Andalusite. It has distinctive cross-shaped black inclusions of graphite.
Chiastolite crystals have been pseudomorphically altered by a mixture of muscovite, paragonite and margarite. All three white mica phases are present in an equilibrium assemblage.