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The Rock Cycle. By Your Name Here. Rocks are hard substances found in and on the earth’s crust. Rocks are made up of minerals, solids that can form crystals. Gypsum, graphite, flint, and mica are minerals. .
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The Rock Cycle By Your Name Here
Rocks are hard substances found in and on the earth’s crust.
Rocks are made up of minerals, solids that can form crystals. Gypsum, graphite, flint, and mica are minerals.
Crystals have definite shapes with flat surfaces and sharp edges. Diamonds, rubies, and quartz are crystals.
Some minerals are metals, malleable and ductile substances which conduct electricity.
Rocks are formed when magma from the earth’s mantle rises toward the earth’s surface.
Magma which cools slowly inside the earth forms intrusive igneous rock such as granite.
Magma which erupts from a volcano and cools quickly forms extrusive igneous rock such as pumice and obsidian.
The igneous rock may be also physically weathered by running water.
The igneous rock may be physically weathered by rapid temperature changes in deserts.
Germinating seeds and expanding plant roots may also physically weather rock.
Water which freezes in cracks may also push apart and weather rocks.
Other types of rock may also be physically or chemically weathered.
Chemical weathering occurs when acids from rainwater breakdown rock.
Acids from lichens and moss can also chemically weather rock.
Weathered bits of rock called sediments are moved by erosion.
A conglomerate is a sedimentary rock made up of pebbles and sand.
Limestone is a sedimentary rock made up of shells and the skeletal remains of sea creatures.
The igneous rock granite can be changed into the metamorphic rock gneiss.
The movement of tectonic plates forces igneous, sedimentary, and metamorphic rock toward the mantle.