Helium.com | Ecology & Environment | The differences between igneous rock and metamorphic rock http://www.helium.com/knowledge/291019-the-differences-between-igneous-rock-and-metamorphic-rock.xml Helium.com > Ecology & Environment > The differences between igneous rock and metamorphic rock en-us Copyright Helium.com Mon, 02 Nov 2009 20:03:00 GMT Mon, 02 Nov 2009 20:03:00 GMT There are 3 main types of rock, which are igneous, sedimentary and metamorphic Igneous rock: Igneous rocks are crystalline solids which form direc... http://www.helium.com/items/1673396-the-difference-between-igneous-rock-and-metamorphic-rock Sat, 05 Dec 2009 21:35:34