Hornblende
Physical Properties
| Color | dark green |
| Form/Habit | massive |
| Lusture | vitreous |
| Streak | white |
| Hardness | 5-6 |
| Cleavage | perfect two sets |
| Fracture | uneven |
| Specific Gravity | 3.0-3.5 (moderate) |
| Chemical Composition | Ca2(Fe, Mg, Al)5(Al, Si)8O22(OH)2 |
| Crystal System | monoclinic |
| Diagnostic Properties | perfect two set cleavage |