BH250-67
Title
BH250-67
Subject
Garnet Schist
Description
Major Minerals: biotite, muscovite, quartz
BH250-67 is a biotite-muscovite schist collected from the Black Hills of South Dakota. This sample displays excellent foliation, characteristic of regional metamorphism, with well-aligned platy micas creating a distinct schistosity. The quartz grains exhibit beautiful undulose extinction under cross-polarized light, indicative of dynamic recrystallization. Several quartz crystals are ideal for obtaining interference and uniaxial figures, making this an excellent teaching and research specimen for optical mineralogy.
BH250-67 is a biotite-muscovite schist collected from the Black Hills of South Dakota. This sample displays excellent foliation, characteristic of regional metamorphism, with well-aligned platy micas creating a distinct schistosity. The quartz grains exhibit beautiful undulose extinction under cross-polarized light, indicative of dynamic recrystallization. Several quartz crystals are ideal for obtaining interference and uniaxial figures, making this an excellent teaching and research specimen for optical mineralogy.
Coverage
Location: Black Hills, South Dakota, USA
Date
November 17, 2009
Creator
Bereket Haileab
Source
From the rock collection of Bereket Haileab. Sample 66. Housed at Carleton College in Minnesota.
Type
Thin section
Relation
Collection
Citation
Bereket Haileab, “BH250-67,” BH250 Mineralogy Teaching Collection, accessed April 25, 2026, https://bereket-haileab.geology.sites.carleton.edu/items/show/77.