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
Actinolite, Plane Polars
Actinolite, plane polarized light. Magnification: 40x Rock: actinolite schist Click here to watch this grain rotate in XPL: https://youtu.be/WnPAfHkYkM0 Clic…
Actinolite, Crossed Polars
Actinolite, plane polarized light. Magnification: 40x Rock: actinolite schist Click here to watch this grain rotate in PPL: https://youtu.be/_ZSOuxO2q0E Clic…