Felsic Rock

The class of rock which crystallizes from silicate minerals at relatively low temperatures and with relatively high percentage of silica is generally referred to as "felsic" rock. This class includes granite and rhyolite and is at the low temperature extreme of the Bowen reaction series.

An interesting comment from Bjornerud's "Reading the Rocks" gives some perspective ".. one of the first questions to pose to an igneous rock is where it falls on the spectrum from primitive, or mafic (magnesium-rich, silicon-poor), to evolved, or felsic (magnesium-poor, silicon-rich). A mafic rock like basalt generally has tales to tell of life in the mantle, while for a felsic rock like granite, whose progenitors were themselves crustal, the mantle is a nearly forgotten ancestral homeland."