General Information:
Chemical Formula:
(Na,Ca,K)2(Mn++++,Mn+++)6O12·3-4.5(H2O)
Composition:
(Molecular Weight = 583.05 gm)
Potassium 0.13 % K
Sodium 0.79 % Na
Calcium 0.34 % Ca
Manganese 56.54 % Mn
Hydrogen 1.04 % H
Oxygen 41.16 % O
Empirical Formula:
Na0.2Ca0.05K0.02Mn4+4Mn3+2O12·3(H2O)
Environment:
Primarily found as a constituent mineral in deep sea nodules.
IMA Status:
Approved IMA 1960
Locality:
Todroki mine, Hikkaido, Japan.
Name Origin:
Named for the locality.
Physical Properties:
Cleavage:
[100] Perfect, [010] Perfect
Color:
brownish black, gray, grayish black, dark brown, or black.
Density:
3.49 - 3.82, Average = 3.65
Diaphaniety:
Opaque
Habits:
Nodular - Tuberose forms having irregular protuberances over the surface., Reniform - "Kidney like" in shape (e.g.. hematite)., Aggregates - Made of numerous individual crystals or cl usters.
Hardness:
1.5 - Between Talc and Gypsum
Luster:
Metallic - Dull
Streak:
dark brown
More details...