mineral

Staurolite

Staurolite (Fe2Al9O6(SiO4)4(O,OH)2)

Hardness: 7 to 7.5 on the Mohs scale. Color: Brownish black, reddish brown, or yellowish brown. Luster: Vitreous to resinous, sometimes dull. Crystal structure: Monoclinic, frequently forming distinctive 60-degree or 90-degree cruciform penetration twins (fairy crosses). Cleavage: Distinct on {010}, poor on {100}.…

Hardness: 7 to 7
Color: Brownish black, reddish brown, or yellowish brown
Luster: Vitreous to resinous, sometimes dull

Identified August 2, 2026More mineral →

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Physical properties

Formation & geological history

Formed through regional metamorphism of argillaceous rocks such as pelitic schists and gneisses, commonly associated with minerals like garnet, kyanite, and sillimanite.

Uses & applications

Used primarily as a collector's mineral, for jewelry and amulets when naturally twinned into crosses, and historically as an abrasive or in industrial sandblasting.

Geological facts

Known commonly as the 'fairy cross' or 'fairy stone', staurolite twins have been prized for centuries as good luck charms and religious symbols due to their natural cross-like shape.

Field identification & locations

Easily identified in the field by its distinct prismatic crystals and characteristic cross-shaped twinning. Commonly found in metamorphic terrains worldwide, including parts of Virginia, New Mexico, Georgia, and various European localities.