Tephroite
Chemical Formula	Mn2SiO4
Species	Silicates
Crystal System	Orthorhombic
Mohs Scale	6
Specific Gravity	3.87-4.12
Color	Olive-green, bluish green, gray, °esh-red, reddish brown; pale green in thin section, may be colorless
Streak	Pale gray
Luster	Vitreous, Greasy
Refractive Index	n = 1.759 n = 1.797 n = 1.860
Diaphaneity	Translucent
Cleavage	Distinct/GoodDistinct on Imperfect on
Fracture	Irregular/Uneven, Conchoidal
Crystal Habit：Crystals typically short, prismatic, to 4 cm, or anhedral, equidimensional. Commonly in disseminated grains, compact, or massive.
Geological Setting：In Fe-Mn ore deposits, skarns, and metamorphosed manganese rich sediments.