Rocks
By Michael Kress
All rock are made of crystals and are identified by where they are found and they look like and feel like.
Igneous Rocks
Are formed by melting and solidification. They form inside the earth's crust. The types are intrusive and extrusive. Extrusive(volcanic) and Intrusive(plutonic).
Sedimentary Rocks
Are formed by cementation. Are normally found at or near earth's surface. The types are clastic, bioclastic, and crytalline. Clastic: particles cemented together. Bioclastic: rocks formed by plant or animal remains.
Metamorphic Rocks
Formed by heat and pressure. They are formed deep within the earth (up to 20 km). The types are foliated and non foliated. foliated and non foliated: alignment of minerals in a metamorphic rock.
Rhyolite
Is an extrusive rock that formed slow from the cooling of magma. The crystal size is less than 1mm and its texture is fine. Its non vesicular. Its color is a vary of light colors and has a low density. Its made of potassium feldspar, quartz, plagioclase feldspar,biotite, and amphibole.
Dolostone
Is chemically formed. Its grain size is fine too coarse crystals. Its texture is crystalline. Its composition is dolomite. Crystals from chemical precipitates and evaporates.
Metaconglomerate
Its texture is non foliated. Its grain size is coarse. Its composition is various minerals. Its type of metamorphism is regional or contact. Pebbles may be distorted or stretched.
Rock Cycle
The rock cycle is a model showing how rocks and sediments change over time..