BH250-3
Title
BH250-3
Subject
Garnet Mica Schist
Description
Major Minerals: garnet, muscovite, quartz
Minor Minerals: chlorite
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Minor Minerals: chlorite
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BH250-3 is a garnet schist, a highly schistose, medium- to high-grade metamorphic rock dominated by garnet and mica. The rock contains euhedral garnets that show signs of retrograde metamorphism, evidenced by the formation of chlorite along the margins and cracks, particularly in the "fish-tail" terminations of the garnets.
Notably, the rock also features mica fish—distinctive, lens-shaped or elongate mica crystals aligned within the foliation. These structures are common in deformed metamorphic rocks and serve as indicators of shear sense and strain localization. The presence of both garnet fish and mica fish suggests dynamic metamorphism, with deformation and metamorphic reactions occurring simultaneously.
Creator
Bereket Haileab
Source
From the rock collection of Bereket Haileab. Sample BH250-3. Housed at Carleton College in Minnesota.
Type
Thin section
Relation
Collection
Citation
Bereket Haileab, “BH250-3,” BH250 Mineralogy Teaching Collection, accessed April 25, 2026, https://bereket-haileab.geology.sites.carleton.edu/items/show/3.