Category:Volcanic

Vol*can"ic, a. Etym: [cf. F. volcanique, it. vulcanico.]

1. Of or pertaining to a volcano or volcanoes; as, volcanic heat.

2. Produced by a volcano, or, more generally, by igneous agencies; As, volcanic tufa.

3. Changed or affected by the heat of a volcano. Volcanic bomb, a Mass ejected from a volcano, often of molten lava having a rounded Form. -- volcanic cone, a hill, conical in form, built up of cinders, Tufa, or lava, during volcanic eruptions. -- volcanic foci, the subterranean centers of volcanic action; the Points beneath volcanoes where the causes producing volcanic Phenomena are most active. -- volcanic glass, the vitreous form of lava, produced by sudden Cooling; obsidian. See obsidian. -- volcanic mud, fetid, sulphurous mud discharged by a volcano. -- volcanic rocks, rocks which have been produced from the Discharges of volcanic matter, as the various kinds of basalt, Trachyte, scoria, obsidian, etc., whether compact, scoriaceous, or Vitreous.