Researchers in Germany have used igneous rock from the outpourings of Mount Etna to catalyze the formation of carbon nanotubes. Dang Sheng Su and colleagues at the Fritz Haber Institute in Berlin have found naturally occurring iron oxide particles in lava make it an effective natural catalyst. The work opens up a renewable and cheap approach to mass producing nanotubes and nanofibers. Crushing of iron oxide rich cooled lava and high temperature treatment with hydrogen gas, reduces the oxide to nanoscopic particles of iron oxide, which can template the deposition of carbon from a hydrogen-ethylene gas mix at relatively moderate temperatures. Their work also points to the possibility that, given the presence of methane and hydrogen in volcanic gases, carbon nanotubes might form naturally in volcanoes or on extraterrestrial worlds.