More on Igneous Rocks from Infoplease:

• rock - rock rock, aggregation of solid matter composed of one or more of the minerals forming the ...
• igneous rock - igneous rock: igneous rock: see rock.
• rock: Igneous Rocks - Igneous Rocks Igneous rock originates from the cooling and solidification of molten matter from the ...
• porphyry, igneous rock - porphyry porphyry , igneous rock composed of large, conspicuous crystals (phenocrysts) and a ...
• Igneous Rocks - Igneous Rocks Those which have been produced by the agency of fire, as the granitic, the trappean, ...