Classifying Rocks

Igneous rocks are classified according to their origin, texture, and mineral composition. Origin Did it harden inside the earth or on the earth’s surface? Texture Is it fine or coarse grained? Mineral Composition dark colored Is it dark colored, which is low in silica or light colored, which is high in silica?

from lava from magma

Which of the following igneous rocks are extrusive? How do you know?

Sedimentary rocks are formed by sediment that is deposited over time, usually as layers at the bottom of lakes and oceans. This sediment can include minerals, small pieces of plants or other organic matter. It is compressed over a long period of time before creating a rock. Fossils can be found in sedimentary rock.

Sedimentary Rock clastic chemical organic from rock particles Categorized by: particle size shale sandstone conglomerate from once living organisms… plants & animals coal limestone from dissolved minerals in solutions or water that crystallizes rock salt gypsum plant animal

Metamorphic Rocks Metamorphic rocks are formed when other rocks are exposed to years of heat and pressure. Foliated : grains are arranged in layers, or “bands.” Non-foliated : no layered “bands.” phylite gneiss schist slate marble quartzite

Metamorphic Rocks Follow the arrows!

granite marble

limestone

Metamorphic Rocks Slate Shale Sandstone Quartzite

That was fun!