Rocks
By Zoe Faith
Rocks
Rocks are composed of minerals. They are classified by how they are formed. There are three types of rocks Igneous, Sedimentary, and Metamorphic.
Rhyolite (Igneous)
- Crystals formed fast, formed Extrusive (outside)
- Fine texture, Crystal Size less then 1mm
- Non-Vesicular
- Light color, Low density, Felsic composition
- 75% Potassium Feldspar, 45% Quartz, 25% Plagioclase Feldspar, 16% Biotite, 5% Amphibole
Breccia (Sedimentary)
- Inorganic Rock
- Clastic Texture, pebbles, cobbles, and/or blouders
- Mostly Quartz, Feldspar, and other minerals
- Angular Fragments
Anthracite Coal (Metamorphic)
- Non-Foliated Texture
- Grain size: Fine
- Composition: Carbon
- Regional Metamorphism
- Metamorphism of Bituminous Coal
Rock Cycle
The Rock Cycle -
Is a model showing how rocks and sediments are formed or changed over time. There are two kinds of processes, external and internal. External occurs in the Earths surface while Internal occurs within the Earth.
Sedimentary Rocks
- Formed by Compaction and Cementation
- Formed near or at Earths surface
- Types are Clastic (fragmental), Bioclastic (Organically), and Crystalline (Chemically)
Metamorphic Rocks
- Formed by Heat and Pressure
- Formed deep within the Earth
- Types: Foliated (Preasure) and Nonfoliated (Heat)
Igneous Rocks
- Formed by melting and solidification
- Formed in Volcanoes
- Types are Intrusive (Slow cooling, Big Crystals) and Extrusive (Fast Cooling, Small Crystals)