Granodiorite

The field of view in the photo is 4 mm across. The highly twinned mineral is plagioclase; the clear, untwinned, white to pale yellow mineral is quartz; orthoclase is the grain in the upper left corner; there is a hornblende grain (with high relief) in the upper right corner. The mineralogy of granodiorites is similar to that of granites, but granites contain more alkali feldspar.

Occurrence:

Granodiorites are abundant in orogenic batholiths.