General Information:
Chemical Formula:
SrMn++++6Mn+++2O16
Composition:
(Molecular Weight = 783.11 gm)
Strontium 11.19 % Sr
Manganese 56.12 % Mn
Oxygen 32.69 % O
Empirical Formula:
SrMn4+6Mn3+2O16
Environment:
Post-Alpine stage of veining. Sr end-member of the cryptomelane group.
IMA Status:
Approved IMA (Dana # Added)
Locality:
Found at the Praborna manganese mine, near Saint-Marcel, Aosta Valley, Italian Alps.
Name Origin:
The name reflects the presence of strontium and the black color, melanos in Greek.
Physical Properties:
Cleavage:
[???] Distinct
Color:
black.
Diaphaniety:
Opaque
Habits:
Anhedral Grains - Granular minerals without the expression of crystal shapes, Microscopic Crystals - Crystals visible only with microscopes., Inclusions - Generally found as inclusion s in other minerals.
Hardness:
-
Luster:
Sub Metallic
Streak:
sepia brown
More details...