Biotite
| Type | Mineral |
| Luster | Nonmetallic Shiny |
| Hardness | 2.5 – 3 > Fingernail but < Glass |
| Cleavage | Yes Perfect Basal Cleavage |
| Streak | Dark Brown to Black |
| Color | Dark Brown to Black |
| Miscellaneous | Thin Flexible Sheets |
| Type | Mineral |
| Luster | Nonmetallic Shiny |
| Hardness | 2.5 – 3 > Fingernail but < Glass |
| Cleavage | Yes Perfect Basal Cleavage |
| Streak | Dark Brown to Black |
| Color | Dark Brown to Black |
| Miscellaneous | Thin Flexible Sheets |