3 types of rocks include Metamorphic, Igneous, and Sedimentary.
Metamorphic rocks have been modified by a heat, pressure, and chemical process while buried deep underground. Some examples of these rocks are Phyllite, Gneiss, Quartzite, Schist, and Marble.
Igneous rocks are formed from the solidification of molten material. Five types of Igneous rocks are Pegmatite, Andesite, Basalt, Diorite, and Pumice.
Sedimentary rocks are rocks formed by the accumulation of sediments. (A sediment, according to WordCenteral, is a material that settles into a bottom of a liquid) Different kinds of Sedimentary rocks include Limestone, Breccia, Chert, Oil Shale, and Coal.