Geology Home Page
Roger Weller, geology instructor
Chemical Group: silicate
Chemical Formula: HFeAl5Si2O13
Color: brown Streak: gray Luster: vitreous to sub-resinous
Specific Gravity: 3.7 to 3.8
Cleavage: distinct cleavage in one direction
Crystal Forms and Habits:
Staurolit commonly forms interpenetration twins, either at a 60 degree angle
or at a 90 degree angle.
Mineral Associations: a metamorphic mineral, often found in mica schist
Identifying Characteristics: Staurolite does form single crystals, but twinned crystals
make the reputation for this mineral.
Uses: The right angle twins are used in jewelry and are marketed as "fairy crosses".
Occurrences: Georgia, Virginia
Toxicity: when-swallowed- low when inhaled- high