mineral

Staurolite

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

Hardness: 7 to 7.5 on the Mohs scale; Color: Reddish-brown, dark brown, or yellowish-brown; Luster: Vitreous to resinous, sometimes dull; Crystal structure: Monoclinic, frequently forms distinctive 60-degree and 90-degree cruciform penetration twins (fairy crosses); Specific gravity: 3.7 to 3.8.

Hardness: 7 to 7
Color: Reddish-brown, dark brown, or yellowish-brown
Luster: Vitreous to resinous, sometimes dull

Identified August 2, 2026More mineral →

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Physical properties

Formation & geological history

Forms as a regional metamorphic mineral in pelitic rocks such as schists and gneisses, typically under intermediate to high-temperature and pressure conditions, often associated with garnet, kyanite, and sillimanite.

Uses & applications

Used primarily as a collector's mineral specimen, in jewelry due to its natural cross shape (often called 'fairy crosses' or 'fairy stones'), and occasionally as an index mineral in geology to determine metamorphic grade.

Geological facts

Staurolite gets its name from the Greek word 'stauros', meaning cross, due to its common twinning habit that forms crosses. Folklore in Virginia and parts of the southeastern US tells legends of them being tears shed by fairies upon hearing the news of Christ's crucifixion.

Field identification & locations

Easily identified by its characteristic cross-shaped intergrowths and brownish color in schistose matrices. Commonly found in locations such as Patrick County, Virginia, New Mexico, Brazil, and various European metamorphic belts.