Basalt stone is a very common igneous rock. In fact it is the most common rock in the Earth's crust. Almost all oceanic crust is made of basalt stone and basalt stone is a common extrusion from many volcanic regions around the world. It forms from the melting of the upper mantle and its chemistry closely resembles the upper mantle's composition. It is generally silica poor and iron and magnesium rich. Basalt originates from "hot spot" volcanoes, massive basalt flows and mid oceanic ridges.