Garnet-pyroxene-gneiss.

Garnet-pyroxene-gneiss.

The pyrope in this specimen,  Mg3Al2(SiO4)3   is a member of the garnet group with high Mg content, and occurs in high grade metamorphic rocks. The dark bands of mineral appear to be pyroxene, which is a Mg,Fe, silicate  (Mg,Fe)SiO3  sometimes referred to as hypersthene.  The white or light coloured mineral is quartz. The specimen is a gift from Bill Fitches who collected it from the Shai hills, in Ghana.