Rock Classification By: Alicia Paloscio

Rocks can be classified in three different wways. First there are Sedimentary rocks. Sedimentary rocks are rocks formed by the deposition and solidification of sediments transferred by water, ice or wind. These sediments can contain minerals, small pieces of plants and other organic matters. Some examples of sedimentary rocks are Breccia, Conglomerate and Sandstone.
Other different types of rocks can be classified as Metamorphic. Metamorphic rocks are transformations of already existing rocks. High heat and or pressure causes very distinct changes in its physical appearance or its chemical components. Metamorphic rocks can also be separated by either foliated or non-foliated. Some examples of metamorphic rocks are marble, slate and schist.
Igneous rocks are the last type of classification. They have two main ways of being identified, intrusive and extrusive. Extrusive igneous rocks form when the magma or molten rock pours out of the earth's surface, while intrusive rocks form when magma cools slowly below the Earth's surface. Examples of intrusive include Granite, Gabbro, and Dunite. Basalt is the most common extrusive igneous rock.
Geologist use many tools and observations to identify the different types of rocks and group them accordingly. They often use tools such as rock hammers, field books, Brunton compass, and hand lens for studying and mapping rocks in the field. They use observations such as breakage, mineral composition, color and texture to group and separate rocks. These characteristics tells them which type of rock they are looking at.
Metamorphic rocks are found under the surface.
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Created with images by FrankWinkler - "coast elgol isle of skye" • sarajuggernaut - "stones rocks pebbles" • James St. John - "Clinker (Wasatch Formation, Lower Eocene; coal fire metamorphism at 19 ka, Late Pleistocene; large block at Interstate 90 west-bound hilltop rest area, east of Buffalo, Powder River Basin, Wyoming, USA) 5" • James St. John - "Rock salt (halitite) (Lower Member, Salado Formation, Upper Permian; WIPP Storage Level, New Mexico, USA)" • - "rocks"

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