Escalante and Sairecabur have erupted dark andesites, and later also dacites. Mafic enclaves are found in the post-caldera lavas. The colour of the rocks is black, brown or gray. Minerals include amphibole, biotite, bronzite, Ca-containing augite, clinopyroxene, hornblende, magnetite, orthopyroxene, plagioclase, pyroxene and quartz. In addition, apatite, ilmenite, iron oxides and zirconia are found. At least one lava erupted after the caldera-forming eruption contains olivine. Lavas erupted before the caldera-forming eruption of Sairecabur contain glass and have a microlithic texture. The magmas are calc-alkaline with medium-high K content.