Chlorite tutorial Optical mineralogy
Channel: Matt Kohn
Date: 2021-04-29

Several videos of chlorite in thin section, showing typical textures and optical characteristics. Supported by Boise State University and the US National Science Foundation.
Key characteristics: pleochroic in light green, low/moderate relief, pleochroic haloes, anomalous interference colors.
00:00 Typical single crystal with green pleochroism
00:30 Subtle pleochroism, anomalous blue interference colors
01:00 In an amphibolite (for comparison to hornblende)
01:30 Unusual orientation (looking down on a cleavage face)
02:00 Deformed crystal with ilmenite inclusions
02:30 Both anomalous brown/green and blue interference colors
03:00 Beautiful blue interference colors
03:31 Unusual purple interference colors