Physical Properties |
|
| Chemical formula | Ca2(Fe,Mg)5Si8O22(OH)2 |
| Class | Inosilicate Double chains of linked tetrahedra |
| Crystal system | Monoclinic |
| Habit | Acicular, typically radiating or forming parallel aggregates Columnar masses |
| Color | Dark green |
| Hardness | 5 to 6 |
| Specific gravity | 3.0 to 3.3 |
| Cleavage | Two perfect prismatic {110} |
| Fracture | Uneven |
| Luster | Vitreous |
| Transparency | Transparent to translucent |
| Streak | White |
Optical Properties |
|
| PPL | Colorless to green Pleochroic “60/120” cleavage (actually 56° and 124°) |
| XPL | Upper 1st to 2nd order interference colors |
| δ | 0.03 |
| after Perkins, 332 |
Actinolite in Hand Sample
Actinolite
Actinolite in quartz
Actinolite replacing spinifex olivine in a meta-komatiite
Scanning electron micrograph of actinolite
Actinolite in Thin Section
Thin Section GigaPans
Actinolite in actinolite schist, plane polars
Actinolite in actinolite schist, crossed polars
