MAjor Rock Types

“United States Geological Survey.” United States Geological Survey - an Overview | ScienceDirect Topics, https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/united-states-geological-survey.

“Pictures of Sedimentary Rocks.” Geology, https://geology.com/rocks/sedimentary-rocks.shtml.

Sedimentary:

Sedimentary rocks are formed from pre-existing rocks or pieces of once-living organisms. They form from deposits that accumulate on the Earth's surface. There are many types of sedimentary rocks, including sandstone, limestone, and shale. These rocks are usually carried by rivers and deposited in lakes and oceans (United States Geological Survey).

Major Types of Sedimentary Rocks: Clastic Sedimentary Rocks, Chemical Sedimentary Rocks, Biochemical Sedimentary Rocks, and Organic Sedimentary Rocks. The formation of a clastic sediment/sedimentary rocks involves five processes: Weathering, Eroison, Transportaion, Deposition, Lithification (United States Geological Survey).

Clastic Sed. ex: Breccia, Conglomerate, Sandstone, Siltstone, and Shale.

Chemical Sed. ex: Chert, (some dolomites), Flint, Iron ore, Limestones, and Rock salt.

Organic Sed. ex: Chalk, Coal, Diatomite, and Limestones.

Igneous Rocks:

Igneous rocks form when magma (molten rock) cools and crystallizes, either at volcanoes on the surface of the Earth or while the melted rock is still inside the crust. Igneous rocks contists of extrusive and intrusive rocks. Extrusive rocks are the rocks that emerge to the surface of the Earth from the magma. This is lava which has been erupted to the surface, or magma that has solidified. Intrusive rocks are normally formed from magma, which is the cooled and hardened mixture of solidified molten (United States Geological Survey).

Extrusive ex: Andesite, Basalt, Dacite, Obsidian, Pumice, Rhyolite, Scoria, and Tuff.

Intrusive ex: Diorite, Granite, and Pegmatite.

“What Are Sedimentary Rocks?” What Are Sedimentary Rocks? | U.S. Geological Survey, https://www.usgs.gov/faqs/what-are-sedimentary-rocks.

Metamorphic Rocks :

Metamorphic rocks began out as some other type of rock,but have been considerably changed from their unique igneous,sedimentary,or earlier metamorphic form. Metamorphic rocks form when rocks are subjected to high heat, high pressure, hot mineral-rich fluids or, more commonly, some combination of these factors (United States Geological Survey).

Metamorphic ex: Phyllite, Schist, Gneiss, Quartzite and Marble.

Yellow Calcite: consist largely of calcium carbonate (CaCO3). Calcite found near the Earth's surface usually takes on yellowish colors from iron oxide staining

Yellow Calcite: Calcite, the essential ingredient of limestone, is generally white or distinct in its crystalline form in sedimentary and metamorphic sedimentaries.

Amethyst: Silicon dioxide (SiO2). Amethyst is a violet variety of quartz. It contains iron and other trace minerals within its structure.

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