Granite is an igneous rock in the class designated as "felsic" rock. This class of rock crystallizes from silicate minerals at relatively low temperatures and with relatively a high percentage of silica . It is at the low temperature extreme of the Bowen reaction series.
Granite is probably the best known of all igneous rocks. It is abundant and it is widely used in both construction and decoration. Many types of granite have great beauty when polished. In texture it is classified as phaneritic. Granite has 25 to 35% quartz in roughly spherical crystals. They may be clear to light gray. It has over 50% potassium feldspar and sodium-rich plagioclase. The feldspar crystals are more rectangular in shape and are usually white to gray or salmon-pink in color.
Igneous rock concepts
Lutgens & Tarbuck