notes+4.2

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Vocabulary

 * vein**-a slab of mineral where it is different from the other rocks
 * solution**- a mixture where one substance dissolves in another

Processes That Form Minerals

 * minerals that have been forming in Earth's Crust for billions of years
 * two ways crystals form
 * through crystallization of melted materials
 * through crystallization of materials dissolved in water

Materials From Magma

 * minerals form as magma cools inside crust or lava on the surface
 * when these liquids cool, they form crystals
 * crystal size depends upon several key factors
 * the rate of cooling
 * how much gas in the liquid
 * the chemical composition of the magma
 * when magma stays below surface, it cools for thousands of years
 * slow cooling forms large crystals
 * Magma closer to the surface,cools rapidly
 * quick cooling creates smaller crystals

Minerals From Hot Water Solutions

 * the elements that form a mineral can also dissolve in hot water
 * magma heats the water under Earth's surface to a high temperature
 * dissolved minerals form solutions
 * When it begins to cool,the compounds and elements leave the solution
 * Soon, they crystallize as minerals
 * metals that form underground from hot water solutions often form veins
 * solutions of hot water and metal often seep through cracks underground
 * the metal then crystallize into veins
 * minerals can form along the mid-ocean ridge
 * first the ocean water sinks through the ocean crust
 * the water comes in contact with the magma
 * the water heats to a very high temperature
 * the heated water dissolves minerals and rushes upward
 * this solution sprays out of chimneys(vents in the oceanic crust)
 * when the solution hits the sea the minerals crystallize and sink to the ocean floor

Minerals Formed by Evaporation

 * minerals can also form by evaporation
 * if you mix salt with water to make a solution,the water will evaporate and you will see salt crystals at the bottom of the cup
 * the mineral, halite forms from evaporation
 * Some minerals form from evaporation of seawater
 * these minerals are gypsum, calcite crystals, and minerals containing pottasium

Where Minerals are Found
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 * the crust is mostly made up of rock forming minerals
 * many valuble minerals are found near volcanic activity and mountain building
 * California's gold was found along the Sierra Nevada mountains