Wollastonite
Transmitted Crossed Polarized Light with the Red Plate Compensator
The long axis of the wollastonite prisms is oriented along the beta refractive index. As
a
result the fiber will exhibit a positive or negative sign of elongation depending on how
the
the fiber is rotated around its long axis. In this image two blue wollastinite fibers
are
shown. One of the fibers has the gamma refractive index oriented across the long axis
(NW-SE)
and the other has alpha oriented across the long axis (NE-SW). The blue fiber orriented
Northwest-Southeast is rather faint because the beta refractive index is closer to gamma
than it is to alpha.