Gypsum crystal, mounted with its optic normal perpendicular to the spindle axis.



A gypsum crystal (monoclinic) is mounted with its ON perpendicular to the axis of rotation of the spindle stage and rotated through 90 degrees on the spindle stage. The three videos below show the crystal in plane polarized (nothing too cool), cross-polarized (the crystal rotates from a centered BXA to a centered OA to a centered BXO and back again), and lastly, in conoscopic light (the crystal rotates from a centered BXA to a centered OA to a centered BXO and back again).

Plane polarized light

Cross polarized light

Conoscopic illumination


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