Monzonite

Thursday, June 10, 2010

Monzonite is an intermediate igneous intrusive rock composed of approximately equal amounts of sodic to intermediate plagioclase and orthoclase feldspars with minor amounts of hornblende, biotite and other minerals. Quartz is a minor constituent of monzonite. When it contains more than 10% of quartz, the rock is then called a quartz monzonite. If monzonite has more orthoclase or potassium feldspar it grades into a syenite. With an increase of calcic plagioclase and mafic minerals the rock type becomes a diorite. The volcanic equivalent is the latite.

Monzonite