Name:  Tourmaline-Mica Schist

Geologic Name:  None

Reference:  Van Hise, C.R., The Pre-Cambrian rocks of the Black Hills:
Geol. Soc. America Bull v. 1, p. 227-228, 1890.

Microscopic characters:  Schistose texture.  The slide is composed of
microcline, tourmaline, quartz, biotite, muscovite, and orthoclase.
The tourmaline metacrysts, which are usually oriented parallel to the
schistoscity, contain numerous inclusions of quartz, microcline and
orthoclase which are aligned roughly parallel to the c-axis of their
host.  The large microcline crystals also contain many oriented
inclusions of quartz.