ROCK TYPES     I. ROCKS--Aggregates of Minerals A. Monominerallic--one mineral type e.g. quartzite -- 100% quartz B. Polyminerallic--2 or more mineral types II. 3 ROCK TYPES A. Igneous--("ignus"= fire) 1. Form due to the crystallization of molten rock a. Magma--molten within the Earth. b. Lava--molten rock on the surface B. Sedimentary--(Sedimentu = to settle) 1. Formed from sediments which may consist of remains of plants or animals, pre-existing rock fragments, or chemical precipitates C. Metamorphic--"changed in form" 1. Changed in texture and/or composition due to heat, pressure, and chemically active fluids III. ROCK CYCLE A. Weathering--response of materials in contact with water, air, or living matter B. Lithification--process of consolidating sediments 1. Compaction 2. Cementation