Several videos of talc in thin section, showing typical textures and optical characteristics. Supported by Boise State University and the US National Science Foundation.
Key characteristics: low relief, good cleavage, high interference colors, birds’ eye extinction (indistinguishable from muscovite, so association with Mg-rich minerals can be important)
00:00 Coarse, with actinolite in metasomatized rock
00:3 Same, good birds’ eye extinction
01:01 Coarse talc showing range of interference colors
01:32 In altered ultramafic rock with olivine
02:03 Another example of the same
02:34 Fine-grained alteration of Mg-rich garnet
