Reflected/Transmitted light color: colorless
Pleochroism: absent
Optical isotropy/anisotropy: biaxial
Optical sign: -
| Albite (An0) | Anorthite (An100) | |
| na | 1.527 | 1.577 |
| nb | 1.531 | 1.585 |
| ng | 1.538 | 1.59 |
| ng-a | 0.01 | 0.013 |
| 2V | 77 | 78 |
| Disperson | r>v | v>r |
Extinction agnel: oblique 5-to 19 degrees with respect to (001)