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How Minerals Form In general, minerals form in two ways: . By crystallization of magma & lava By crystallization of materials dissolved in water. . Crystallization is the process by which atoms are arranged to form a material with a crystal structure.
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How Minerals FormIn general, minerals form in two ways: • By crystallization of magma & lava • By crystallization of materials dissolved in water.
Crystallization is the process by which atoms are arranged to form a material with a crystal structure.
A geode is a rounded hollow rock that is often lined with mineral crystals.
Minerals From Magma & Lava Minerals form as hot magma cools inside the crust or when lava hardens on the surface.
The size of the crystal depends upon several factors: • The rate (speed) at which the molten material cools. • The amount of gas in the molten material. • The chemical composition of the molten material (or what elements/chemicals make up the molten rock.
Magma deep inside the earth takes thousands of years to cool. Slow cooling results in large crystals.
Magma close to the earth’s surface or lava that cools on the surface will cool more quickly.
Rapid cooling results in small crystals….sometimes microscopic.
Minerals From Solutions Elements/Compounds that form minerals may sometimes be dissolved in water to form a solution.
When elements/compounds that are dissolved in water leave a solution, crystallization can occur.
Minerals Formed by Evaporation Some minerals form when solutions evaporate. Large deposits of halite in the USA formed this way.
Minerals From Hot Water Solutions Underground, magma can heat water to high temperatures. Elements/Compounds may become dissolved in this hot solution.
When the water solution cools the elements and compounds crystallize as minerals.
Pure metals that crystallize from hot water solutions underground often form veins.
A vein is a narrow channel or slab of a mineral that is different from the surrounding rock.