Quartz latite

Quartz latite
Volcanic rock
A boulder of quartz latite from the Cerro Rubio plug, Jemez Mountains, New Mexico, USA. Field of view is about 50 cm.
Composition
Intermediate
Major minerals: plagioclase, alkali feldspar, quartz

A quartz latite is a volcanic rock or fine grained extrusive rock composed mostly of alkali feldspar and plagioclase with some quartz. It forms from the rapid cooling of magma of intermediate composition but moderately enriched in alkali metal oxides.

Quartz latite is intermediate between latite and rhyolite in its mineralogy.