The rocks you see around you - the mountains, canyons & riverbeds, are all made of minerals. A rock is made up of 2 or more minerals. Think of a chocolate chip cookie as a rock. The cookie is made of flour, butter, sugar & chocolate. The cookie is like a rock and the flour, butter, sugar & chocolate are like minerals. You need minerals to make rocks, but you don't need rocks to make minerals. All rocks are made of minerals.

Rocks are mixtures of minerals (grains) cemented and pressed together Most rocks are composed of at least 2 minerals Example of a rock: Granite: contains 75% feldspar, 20% quartz, and 5% mica Color and TEXTURE to determine the rocks mineral composition. TEXTURE: Grain size: coarse grained- easy to see fine grained- need a microscope to see. no grain- texture similar to glass Texture: physical features, how the grains of the rock are arranged Grain: particles of minerals that make up the rock

Rocks are classified by how they formed and what they’re made of There are 3 general classes of rocks Igneous Rocks…are formed when lava and magma crystallize to form solid rock Metamorphic Rocks…are formed when an existing rock is partially melted, squeezed, or both Sedimentary Rocks…are formed when sediments (sand clay, and silt) are compressed and become solid rock

Extrusive: Cools outside the earth- very small crystals glassy: fine or no grain Intrusive: Cools inside the earth- large crystals easy to see: coarse grain Igneous Rocks

SILICA: contained in most of the Earth’s Rocks… Otherwise know as Quartz…. If an Igneous rock is light in color… than it is high in silica If an Igneous Rock is dark in color than it is low in silica Uses of Igneous Rocks… Tools and building materials Granite is used for building materials, statues and bridges Basalt=gravel

Sedimentary Rock EROSION: Rocks are eroded into sediment DEPOSITION: Sediment is deposited onto the Earth COMPACTION: Over millions of years, layers of sediment build up and press together CEMENTATION- Minerals in the rock dissolve into water. Water seeps in between sediment particles. Dissolved minerals recrystalize and “GLUE” the sediment together. Sedimentary Rock can be organic or inorganic….. Most of the world’s ocean floors contain limestone that formed from the shells of dead marine organisms

Sedimentary rock can be Clastic. Clastic is when rock fragments are squeezed together Conglomerate: pebbles are glued together Breccia: Sharp fragments of rocks are glued together

Sedimentary Rocks can be CHEMICAL Chemical means that the rock is formed from the evaporation of water - the resulting rock is called a Chemical rock USES of sedimentary rock…. Building materials (The White House is built of sandstone) Limestone: makes cement

The Origin of Metamorphic rock: Rocks that have changed due to… HEAT AND PRESSURE!!!! Causes changes in the composition of the rock Metamorphic Rocks are classified by: FOLIATED: minerals line up and form bands Non-FOLIATED: minerals change but don’t form bands