By Nick Barao
What a rock is
Rocks are composed of minerals. Rocks are classified by how they were formed. There are three types of rocks.
- They are made from melting and solidification
- They can be glassy, have vesicles, or have interconnected crystals
- They either formed inside a volcano (intrusive) or outside a volcano (extrusive).
- Intrusive rocks crystallizes slowly inside the earth's crust and contain large crystals
- Extrusive rocks crystallizes quickly at the earth's surface and contain small crystals.
- They are formed by cementing and compaction
- They are formed on the earth's surface
- They can be Crystalline - crystals from chemicals precipitates and evaporates , formed chemically
- They can be Bioclastic - formed organically
- They can be Clastic - formed inorganically
SOME DIFFERENT ROCKS!
It formed outside the volcano and the crystals formed fast. The texture is fine and non-vesicular. The crystal size is less than 1 mm. The color is dark. The density is high. The composition is mafic. It has the minerals plagioclase feldspar, pyroxene, and amphibole. It is 30% plagioclase feldspar, 60% pyroxene, and 10% amphibole
Is Chemically formed. The grain size can be fine to coarse. Texture is crystalline. Its composition is made of halite. Crystals from chemical precipitates and evaporates.
Texture is non-foliated. Grain size is fine. Its composition is made up of various minerals. It was created by contact metamorphism. Various rocks changed by heat form nearby magma/lava.
THE ROCK CYCLE!
If an igneous rock gets weathered and erosion occurs it becomes sediment. Then if those sediments get deposited , burial, compacted, and cemented, it become a sedimentary rock. If the sedimentary Rock goes through metamorphism, it becomes a metamorphic rock. IF that metamorphic rock melts it becomes magma. If the magma solidify it becomes an igneous rock. Magma can't become sediments and sediments can't become magma. weathering and erosion cause metamorphic rocks, sedimentary rocks, igneous rocks, and sediments to become sediments.