Alleghanyite

General Information:
 Chemical Formula:
Mn5(SiO4)2(OH)2
 Composition:
(Molecular Weight = 492.87 gm)
Manganese 55.73 % Mn
Silicon 11.40 % Si
Hydrogen 0.41 % H 
Oxygen 32.46 % O 
 Empirical Formula:
Mn2+5(SiO4)2(OH)2
 Environment:
Manganese vein deposits.
 Locality:
TL: Bald Knob, Alleghany Co., North Carolina, USA.
 Name Origin:
Named after its locality.
Physical Properties:
 Cleavage:
None
 Color:
white, brown, bright pink, or grayish pink.
 Density:
4
 Diaphaniety:
Transparent to Subtransparent to translucent
 Habits:
Massive - Lamellar - Distinctly foliated fine-grained forms., Granular - Generally occurs as anhedral to subhedral crystals in matrix.,
 Hardness:
6-5
 Luminescence:
Non-fluorescent.
 Luster:
Vitreous (Glassy)
More details...

ALLEGHANYITE