Staurolite
Chemical Formula	Fe2+2Al9O6(SiO4)4(O,OH)2[1]
Species	Silicates
Crystal System	Monoclinic
Mohs Scale	7
Specific Gravity	3.74-3.83
Color	Dark reddish brown to blackish brown, yellowish brown, rarely blue; pale golden yellow in thin section
Streak	White to grayish
Luster	Sub-Vitreous, Resinous
Refractive Index	n = 1.736 - 1.747 n = 1.740 - 1.754 n = 1.745 - 1.762
Diaphaneity	Translucent
Cleavage	Distinct/GoodDistinct on
Fracture	Sub-Conchoidal
Crystal Habit：Commonly in prismatic crystals
Geological Setting：Amphibolite grade of regionally metamorphosed pelitic rocks.