Carbonate tutorial Optical mineralogy
Channel: Matt Kohn
Date: 2021-05-03

Several videos of carbonates in thin section, showing typical textures and optical characteristics. Supported by Boise State University and the US National Science Foundation.
Key characteristics: Variable relief, "rough" appearance, colored twins visible in plane-polarized light, super-high (pastel) interference colors, extinction similar to birds' eye.
00:00​ Typical calcite with "rough" appearance and high interference colors
00:30​ Variable relief
00:43 Colored twins
00:55​ Variable relief
01:36​ Ankerite (probably)
02:05 More ankerite, super high interference colors
02:36 Interference figure (off-center but distinctive)