The following photos are from a slide of Ritland Impactite seen through the LOMO Polam P-113 Polarising Microscope. The four photos show the changing colour of the crystals as the polarising filter in the condenser is turned through 90 degrees. There is another polarising filter in the eyepiece assembly. Hence, this slide is being seen with “Crossed Polarising Filters”.
Information on the LOMO Polam P-113 Polarising Microscope can be found here, http://roslistonastronomy.uk/lomo-p-113-polarising-microscope
The following is a video of the same slide through this microscope – showing effect of rotating the polarising filter in the condenser, rotating the rotating stage, and X-Y movement of the stage.