|
Tremolite - Actinolite
|
(AMPHIBOLES) Ca2(Mg,Fe)5[Si8O22](OH,F)2
Crystal system: Monoclinic
Refractive index: 1.599-1.705
Birefringence: 0.027-0.017
Cleavage: two good, 56o
Twinning: simple, lamellar common
Colour in PPL: colourless, pale green, dark green
Pleochroism: present in Fe-rich members
Relief: moderate
Distinction: lamellar twinning not as common nor as fine as in Cummingtonite, more Fe-rich members transitional to
hornblende, distinguished by extinction angle between 10 and 15
Occurrence: regional and contact metamorphic rocks
|
|
HOME | Mineral List | Back: Amphibole Group | Next: Mica Group
|
