With just a few more cents investment, you can create a polarized light microscope from an ordinary microscope. Basically, the microscope mirror is replaced with a polarizer and analyzer. The microscope is still focused in an ordinary way but you should be able to observe dark fields in certain position, of which the general rule is that the darker said fields are, the better the microscope.

Go here to read the rest:
Experiments With a Polarized Light Microscope