Published by Optics for Hire.
We built our own device to look polarization in materials, below we explain how to make your own.
Find the leads that power the screen back light. Solder an old USB cable to the leads.
3-5 volts are required
Similiair units are for sale on Amazon
You could cut the polarizer off an old cell phone, lap top or LCD display
Place polarizing film above magnifier and the cell phone screen below lens
System is powered, polarize film is not in place
But now the polarized film is blocking the light.
As pressure changes you can see colors change
We use this for optics projects, but it is most often used by gemologists to study gems. More information is herehttp://www.gemologyproject.com/wiki/index.php?title=Polariscope