BH250-58
Title
BH250-58
Subject
Tourmaline Bearing Schist
Description
Major Minerals: tourmaline, albite
Minor Minerals: garnet, muscovite, chlorite, orthoclase, quartz
BH250-58 is tourmaline bearing schist. This thin section exhibits prominent schistosity, clearly visible throughout the rock. Tourmaline crystals display schistosity cutting through them, indicating they are syn-tectonic—having grown during metamorphism. When not cut perpendicular to the c-axis, these tourmaline grains show striking pleochroism. Euhedral garnets are present and aligned with the schistosity.
Muscovite is abundant, showing brilliant interference colors, perfect cleavage, and partial alteration to chlorite. Chlorite displays distinctive berlin blue interference colors. Common rock-forming minerals include quartz, plagioclase, and orthoclase. Quartz exhibits undulatory extinction, while feldspars are partially altered to sericite.
Minor Minerals: garnet, muscovite, chlorite, orthoclase, quartz
BH250-58 is tourmaline bearing schist. This thin section exhibits prominent schistosity, clearly visible throughout the rock. Tourmaline crystals display schistosity cutting through them, indicating they are syn-tectonic—having grown during metamorphism. When not cut perpendicular to the c-axis, these tourmaline grains show striking pleochroism. Euhedral garnets are present and aligned with the schistosity.
Muscovite is abundant, showing brilliant interference colors, perfect cleavage, and partial alteration to chlorite. Chlorite displays distinctive berlin blue interference colors. Common rock-forming minerals include quartz, plagioclase, and orthoclase. Quartz exhibits undulatory extinction, while feldspars are partially altered to sericite.
Coverage
From the Himalayas
Creator
Bereket Haileab
Source
From the rock collection of Bereket Haileab. Sample 58. Housed at Carleton College in Minnesota.
Contributor
Bill Dinklage, '89
Type
Thin section
Relation
Collection
Citation
Bereket Haileab, “BH250-58,” BH250 Mineralogy Teaching Collection, accessed April 25, 2026, https://bereket-haileab.geology.sites.carleton.edu/items/show/67.