| Crystal System |
Monoclinic (Pseudo-Orthorhombic) |
| Chemical Comp.. |
(Fe2+,Mg)2(Al,Fe3+,Ti)9O6[(Si,Al)O4]4(O,OH)2 |
| Color |
Pale
Golden Yellow |
| Pleochroism |
Pale
to Gold Yellow |
| Cleavage |
One
Poor to Moderate |
| Relief |
High |
| Birefringence |
1st order White/Yellow |
| 2V | 80˚ to 90˚ |
| Optic Sign | Positive |
| Twinning |
Penetration Twins - rarely seen in thin
section |
The low birefringence colors, high relief, and weak pale yellow pleochroism allow Staurolite to be correctly identified.
It is often full of inclusions. Ch = Chlorite; Qz = Quartz; St = Staurolite; Bi = Biotite.
