General Information:
Chemical Formula:
Mn2SiO4
Composition:
(Molecular Weight = 201.96 gm)
Manganese 54.41 % Mn
Silicon 13.91 % Si
Oxygen 31.69 % O
Empirical Formula:
Mn2+2(SiO4)
Environment:
Contact metamorphism of manganese bearing rocks.
Locality:
Franklin and Sparta, New Jersey, USA.
Name Origin:
From the Greek tephros - "ash gray" for its color.
Physical Properties:
Cleavage:
[010] Indistinct
Color:
gray, olive green, bluish green, red, or reddish brown.
Density:
4.11 - 4.39, Average = 4.25
Diaphaniety:
Transparent to translucent
Habits:
Massive - Granular - Common texture observed in granite and other igneous rock., Granular - Generally occurs as anhedral to subhedral crystals in matrix., Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Hardness:
6.5 - Pyrite
Luminescence:
None.
Luster:
Vitreous - Greasy
Streak:
gray
More details...