Metamorphic Rock Mica Schist and its Thin Section

This is the metamorphic rock mica schist. It’s a coarse-grained rock with parallel orientation of the platy mica minerals biotite and muscovite. This orientation produces prominent foliation, called schistosity. Schists are often abundant in areas with regional metamorphism, and mica minerals are the most common constituents. Other minerals may include quartz and feldspars. Mica schist develops from a variety protoliths through moderate to intense metamorphism. The following clips display this rock’s thin section under a microscope, first in plane-polarized light, and then in cross-polarized light.