Physical Properties |
|
| Chemical formula | Al(OH)3 |
| Class | Hydroxide |
| Crystal system | Monoclinic |
| Habit | Coatings Granular aggregates Colloform masses Radiating masses Tabular, with pseudohexagonal shape |
| Color | White or gray to greenish |
| Hardness | 2.5 to 3.5 |
| Specific gravity | 2.40 |
| Cleavage/fracture | Perfect (001) Uneven |
| Luster | Vitreous Pearly Earthy |
| Transparency | Transparent to translucent |
| Streak | White |
| δ | 0.02 |
| PPL | Colorless |
| XPL | Up to upper 1st order |
| after Perkins, 378 |
Gibbsite in Hand sample
Gibbsite in Thin Section
Gibbsite, plane polars
Gibbsite in plane polarized light. Magnification: 40x Click here for crossed polars: NVCC slide OD 10.
Gibbsite, crossed polars
Gibbsite in cross polarized light. Magnification: 40x Click here for plane polars: https://youtu.be/K_MN_QSujtg NVCC slide OD 10.