General Information:
Chemical Formula:
(Mn++,Mg,Al)3(Si,Al)2O5(OH)4
Composition:
(Molecular Weight = 323.85 gm)
Magnesium 7.51 % Mg
Manganese 25.45 % Mn
Aluminum 8.33 % Al
Silicon 13.01 % Si
Hydrogen 1.24 % H
Oxygen 44.46 % O
Empirical Formula:
Mn2+1.5MgAl0.5Si1.5Al0.5O5(OH)4
Environment:
Metamorphic Mn deposit with other Mn-silicates.
IMA Status:
Approved IMA 1974
Locality:
Bald Knob, Sparta, Alleghany County, North Carolina, USA.
Name Origin:
Named for William Crowley Kelley (1929-), American geologist, University of Michigan.
Physical Properties:
Cleavage:
[001] Perfect
Color:
golden yellow or lemon yellow.
Density:
3.07
Diaphaniety:
Transparent
Habits:
Micaceous - Platy texture with "flexible" plates., Lath - Shaped like a small, thin plaster lath, tabular (rectangular) in shape., Tabular - Form dimensions are thin in one direction.
Hardness:
2.5 - Finger Nail
Luster:
Vitreous - Resinous
Streak:
yellowish white
More details...