BH250-31
Title
BH250-31
Subject
Talc Tremolite Schist
Description
BH250-31 is a metamorphic rock dominated by talc and tremolite. Numerous talc grains are cut perpendicular to the c-axis, allowing excellent interference figures to be observed. Talc displays a BXa(x) biaxial negative interference figure on sections cut perpendicular to the optic axis and shows high birefringence on grains in other orientations.
Talc’s birefringence is similar to that of muscovite, but it is distinguished by its characteristically small 2V angle. Tremolite, also biaxial negative, typically forms during the metamorphism of calcium and magnesium rich sedimentary rocks such as dolostone and limestone, whereas muscovite generally develops from aluminum-rich protoliths.
Talc’s birefringence is similar to that of muscovite, but it is distinguished by its characteristically small 2V angle. Tremolite, also biaxial negative, typically forms during the metamorphism of calcium and magnesium rich sedimentary rocks such as dolostone and limestone, whereas muscovite generally develops from aluminum-rich protoliths.
Creator
Bereket Haileab
Source
From the rock collection of Bereket Haileab. Sample BH250-31. Housed at Carleton College in Minnesota.
Type
Thin section
Relation
Collection
Citation
Bereket Haileab, “BH250-31,” BH250 Mineralogy Teaching Collection, accessed April 26, 2026, https://bereket-haileab.geology.sites.carleton.edu/items/show/35.