We built our own device to look for polarization in materials. Below we explain how to make your own.
Find the leads that power the screen backlight. Solder an old USB cable to the leads.
3-5 volts are required
Cut the polarizer off an old cell phone, laptop or LCD display.
Place a polarizing film above the magnifier and the cell phone screen below the lens.
System is powered. Polarizer film is not in place.
The polarized film is now blocking the light.
As pressure changes, colors change.
Similar units are for sale on Amazon.
We use this for optics projects, but it is most often used by gemologists in their studies. More information is here http://www.gemologyproject.com/wiki/index.php?title=Polariscope