Clintonite tutorial Optical mineralogy

Three videos of clintonite (a rare Ca-Fe-Mg mica) in thin section, showing typical textures and optical characteristics. Supported by Boise State University and the US National Science Foundation.
Key characteristics: pale green to orange pleochroism, moderate relief, good cleavage, but no birds' eye extinction.
00:00​ Characteristic pleochroism
00:33​ Larger grains with excellent cleavage
01:01 Faintly pleochroic