Introduction to Optical Mineralogy

This is an introduction to optical mineralogy that uses plane polarized light and cross polarized light to demonstrate the optical properties of pleochroism and extinction in macroscopic minerals. In the video we make a polariscope and use the polariscope to determine how to differentiate between isotropic and anisotropic minerals. Note that the plane polarized light used is vibrating up-down (or north-south if you prefer). This may be different from your device which could be vibrating left-right (or east-west). This distinction will become more important later on!