| Crystal System |
Orthorhombic |
| Chemical Comp.. |
(Mg,Fe2+)7[Si8O12](OH,F)2 |
| Color |
Colorless
to Pale Green or Yellow |
| Pleochroism |
Feeble
to Moderate: pale yellow, brown-gray |
| Cleavage |
2
@ 126˚ and 54˚ in basal section |
| Relief |
Moderate to High |
| Birefringence |
Maximum first order red-second order
blue |
| 2V | 111˚ to 59˚ |
| Optic Sign | Negative or Positive |
| Twinning |
None |
Anthophyllite
is an orthorhombic amphibole, which means it has straight extinction
when viewed under cross polarized light. The typical amphibole cleavage
can be seen in basal sections. It has low (usually first order)
birefringence and moderate to high relief.