premise: Granite is a rock.
hypothesis: Granite ( [ pronˈɡrænᵻt ] ) is a common type of felsic intrusive igneous rock that is granular and phaneritic in texture . Strictly speaking , granite is an igneous rock with between 20 % and 60 % quartz by volume , and at least 35 % of the total feldspar consisting of alkali feldspar , although commonly the term `` granite '' is used to refer to a wider range of coarse grained igneous rocks containing quartz and feldspar . These rocks mainly consist of feldspar , quartz , mica , and amphibole minerals , which form an interlocking , somewhat equigranular matrix of feldspar and quartz with scattered darker biotite mica and amphibole ( often hornblende ) peppering the lighter color minerals . Granitoid is a general , descriptive field term for lighter-colored , coarse-grained igneous rocks . Granite domes are domical hills composed of granite with bare rock exposed over most of the surface .