Lava Vesuvius between May 14 and June 4, 1737. Serao described "a flow of fiery lava" as an analogy to the flow of water and mud down the flanks of the volcano following heavy rain. The composition of almost all lava of the Earth's crust is dominated by silicate minerals, mostly feldspars, olivine, pyroxenes, amphiboles, micas and quartz. Igneous rocks, which form lava flows when erupted, can be classified into three chemical types: "felsic", "intermediate", and "mafic" (four if one includes the super-heated "ultramafic"). These classes are primarily chemical, however, the chemistry of lava also tends to correlate with the magma
Potrillo volcanic field are five maars in the Potrillo volcanic field. A cinder cone also known as scoria cone, is a steep, conical hill formed on top of a vent. The cinder cones often occur in groups usually on the sides and around the shield volcanoes and the strato volcanoes. They are formed form lava fragments called cinders, it is magma that is glassy and has hundreds of gas bubbles that are frozen, it cools quickly after it is ejected into the air. The lava is expelled from the vent and formed around the vent when they fall back after it is ejected.