metamorphic
Fairy Stone (Staurolite Twin)
Staurolite (Fe2+2Al9Si4O22(OH)2)
Hardness: 7-7.5. Color: Reddish-brown, brownish-black. Luster: Vitreous to dull. Crystal Structure: Monoclinic (pseudo-orthorhombic). It displays a characteristic cross-shaped twinning pattern.
- Hardness
- 7-7
- Color
- Reddish-brown, brownish-black
- Luster
- Vitreous to dull
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Physical properties
Hardness: 7-7.5. Color: Reddish-brown, brownish-black. Luster: Vitreous to dull. Crystal Structure: Monoclinic (pseudo-orthorhombic). It displays a characteristic cross-shaped twinning pattern.
Formation & geological history
Formed through regional metamorphism of aluminous sediments (shales and mudstones) under medium to high temperatures and pressures. Most significant deposits range from the Paleozoic to Precambrian eras.
Uses & applications
Primarily used as a collector specimen and for jewelry (as pendants). Historically used as protective amulets or lucky charms.
Geological facts
The name comes from the Greek 'stauros' for cross. Legend in the Blue Ridge Mountains suggests they are the tears of fairies shed when they heard news of the crucifixion of Christ. They are the state mineral of Georgia, USA.
Field identification & locations
Identify in the field by searching for distinct 'X' or '+' shaped twinned crystals in micaceous schist matrices. Common in Fannin County (Georgia), Virginia, and Taos (New Mexico).
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