Tourmaline tutorial Optical mineralogy
3.8 هزار بار بازدید -
3 سال پیش
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Several videos of tourmaline in
Several videos of tourmaline in thin section, showing typical textures and optical characteristics. Supported by Boise State University and the US National Science Foundation.
Key characteristics: high relief, strongly colored, reverse pleochroism, trigonal end section, moderate interference colors, parallel extinction
00:00 Reverse pleochroism, parallel extinction
00:30 Comparison with biotite (which has normal pleochroism)
01:00 Typical dinky grain
01:30 Cluster of more diagnostic crystals from same rock
02:01 End section with (roughly) trigonal symmetry
02:31 Blue-green crystals
03:01Khaki-colored
Key characteristics: high relief, strongly colored, reverse pleochroism, trigonal end section, moderate interference colors, parallel extinction
00:00 Reverse pleochroism, parallel extinction
00:30 Comparison with biotite (which has normal pleochroism)
01:00 Typical dinky grain
01:30 Cluster of more diagnostic crystals from same rock
02:01 End section with (roughly) trigonal symmetry
02:31 Blue-green crystals
03:01Khaki-colored
3 سال پیش
در تاریخ 1400/02/16 منتشر شده
است.
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