Not required for students of EPS2
| Light Behavior | anisotropic-biaxial |
| Extinction | parallel |
| Color/Pleochroism | colorless |
| Birefringence | first-order grey or white |
| Relief | low negative or low positive |
| Optic Sign | + or - |
| Cleavage | fair to poor |
| 2V | 40-90 degrees |
| Crystal Form | anhedral grains |
| Alteration Products | pinite |
| Twinning | lamellar and cyclic |