General Information:
Chemical Formula:
Fe++2Fe+++(SiFe+++)O5(OH)4
Composition:
(Molecular Weight = 399.50 gm)
Iron 55.92 % Fe
Silicon 7.03 % Si
Hydrogen 1.01 % H
Oxygen 36.04 % O
Empirical Formula:
Fe2+2Fe3+2SiO5(OH)4
Locality:
Pribram and Kuttenberg, Bohemia of Czechoslovakia.
Physical Properties:
Cleavage:
[001] Perfect
Color:
brownish black, greenish black, dark brown, or black.
Density:
3.34 - 3.35, Average = 3.34
Diaphaniety:
Transparent to translucent
Habits:
Pyramidal - Crystals are shaped like pyramids., Divergent - Crystals radiate from a center without producing stellar forms., Amorphous - No crystalline form or imitative shape.
Hardness:
3.5 - Copper Penny
Luster:
Vitreous - Resinous
Streak:
dark olive green
More details...