Muscovite
Physical Properties
| Color | grey-brown |
| Form/Habit | foliated |
| Lusture | vitreous |
| Streak | white |
| Hardness | 2-2.5 |
| Cleavage | perfect 1 set basal |
| Fracture | micaceous |
| Specific Gravity | 2.8 (low) |
| Chemical Composition | KAl2(AlSi3O10)(OH)2 |
| Crystal System | monoclinic |
| Diagnostic Properties | foliated form, hardness, perfect 1 set basal cleavage, micaceous fractures |