Ca2(Mg,Fe)5Si8O22(OH)2Monoclinic
Actinolite
Ca2(Mg,Fe)5Si8O22(OH)2
SilicatesChemical FormulaCa2(Mg,Fe)5Si8O22(OH)2
Crystal SystemMonoclinic
Mohs Hardness5.5
Specific Gravity3.2
ColorGreen to blackish green
LusterVitreous to silky
StreakWhite to grayish
CleavageTwo directions
FractureUneven
Occurrence
Found in metamorphic rocks. Green amphibole. One form of asbestos.