Uturuncu has erupted dacite but also andesite in the form of inclusions within the dacite. Rocks are vesicular or porphyric and contain phenocrysts of biotite, clinopyroxene, hornblende, ilmenite, magnetite, orthopyroxene, plagioclase and quartz along with apatite, monazite and zircon within a rhyolite groundmass, and define a potassium-rich calc-alkaline suite. Xenoliths consisting of gneiss, igneous rocks and norites have also been found, of which the first two appear to be derived from country rocks while the third is a by-product of the magma generation process. Additionally, the occurrence of cumulates, gabbros, hornfels, limestones and sandstones as xenolithic phases has been reported.