mineral
Staurolite
Staurolite (Fe2Al9O6(SiO4)4(O,OH)2)
AI-generated identification · may be incorrectHardness of 7 to 7.5 on the Mohs scale, reddish-brown to black color, vitreous to resinous luster, and monoclinic crystal system. It is well-known for forming distinctive cross-shaped twinning.
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Physical properties
Hardness of 7 to 7.5 on the Mohs scale, reddish-brown to black color, vitreous to resinous luster, and monoclinic crystal system. It is well-known for forming distinctive cross-shaped twinning.
Formation & geological history
Forms regionally through the metamorphism of aluminum-rich pelitic rocks like schist and gneiss, typically in medium-grade metamorphic environments.
Uses & applications
Used primarily as a collector's mineral specimen, educational sample, and occasionally for lapidary purposes or as protective amulets.
Geological facts
Often referred to as fairy crosses or fairy stones due to its natural cruciform twinning habits. It is the official state mineral of Georgia, USA.
Field identification & locations
Identified easily by its characteristic 60-degree or 90-degree penetration twin crosses and dark brownish hue. Found worldwide in metamorphic terrains such as the Southeastern United States and Switzerland.
