Igneous Rocks
Igneous rock is a type of rock that forms from the cooling of molten rock at or beneath the surface. It's one of the three major groups of rocks. Igneous comes from the Greek word "IGNIS" meaning fire. Igneous rocks have two forms, extrusive and intrusive rock. The type of igneous rock it becomes is determined on if the rock was formed from MAGMA and LAVA. There are over 700 different types of igneous rocks found on Earth. If the magma forming the rock cools very quickly, the mineral crystals in the rock will not be visible... (not even under a microscope!)