Magma can solidify in many different ways, so there are many kinds of igneous rock: Like pumice, obsidian is made of cooled lava.
(obsidian; is made; of cooled lava) Context(obsidian is made,List([97, 113))):(Magma; can solidify; )
obsidian is made,List([97, 113))
obsidian Magma
is made can solidify
of cooled lava