For the extinct cephalopod genus, see Andesites.Andesite (/ˈændɨsaɪt/ or /ˈændɨzaɪt/) is an extrusive igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. In a general sense, it is the intermediate type between basalt and dacite, and ranges from 57 to 63% silicon dioxide (SiO2) as illustrated in TAS diagrams. The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende.