General Information:
Chemical Formula:
Ca2(Mg,Fe++)5Si8O22(OH)2
Composition:
(Molecular Weight = 875.45 gm)
Calcium 9.16 % Ca
Magnesium 8.33 % Mg
Iron 12.76 % Fe
Silicon 25.66 % Si
Hydrogen 0.23 % H
Oxygen 43.86 % O
Empirical Formula:
Ca2Mg3Si8O22(OH)2Fe2+2
Environment:
Metamorphic rocks.
IMA Status:
Approved IMA 1978
Locality:
Common world wide.
Name Origin:
From the Greek, aktinos, meaning "ray" in allusion to actinolite's fibrous nature.
Physical Properties:
Cleavage:
[110] Perfect, [110] Perfect
Color:
green, green black, gray green, or black.
Density:
2.98 - 3.1, Average = 3.04
Diaphaniety:
Translucent to transparent
Habits:
Bladed - Aggregates of thin lath-like crystals (e.g. kyanite)., Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite), Fibrous - Crystals made up of fibers.
Hardness:
5.5 - Knife Blade
Luminescence:
Non-fluorescent.
Luster:
Vitreous (Glassy)
Streak:
white
More details...