Presentation on theme: "Section 2 – How Minerals Form"— Presentation transcript:
1 Section 2 – How Minerals Form Chapter 4 – MineralsSection 2 – How Minerals Form
2 How do minerals form from magma and lava? Key ConceptsHow do minerals form from magma and lava?How do minerals form from water solutions?
3 IntroductionGeode – a rounded hollow rock that is often lined with mineral crystals.Formed when water containing dissolved minerals seeps into a crack or hollow in a rock.Slowly, crystallization occurs lining the inside with large crystals that often perfectly formed.
4 Introduction Minerals can form 2 ways Crystallization – the process by which atoms are arranged to form a material with a crystal structure.Minerals can form 2 waysCrystallization of magma and lavaCrystallization of materials dissolved in water.
5 Minerals from Magma and Lava Minerals form as hot magma cools inside the crust.Minerals form as lava hardens on the surfaceWhen these liquids cool to a solid state, crystals form.
6 Minerals from Magma and Lava The size of the crystals depend on several factors:Rate of cooling.Amount of gas contained in magma.Chemical composition of the magma.
7 Minerals from Magma and Lava Magma deep below the Earths surfaceCools over thousands of yearsSlow cooling leads to formation of large crystalsEx. Amethyst crystals in geodeIf undisturbed, growth continues in a regular pattern.
8 Minerals from Magma and Lava Magma closer to the surfaceCools much faster than deep magmaRapid cooling leads to small crystal formationMagma erupting to surface, becoming lava – cools quickly forms minerals with small crystals.
9 STOP and THINK… What is the definition of a solution? Give an example of a solution.
10 Minerals from Solutions Quick review:Solution: a mixture in which one substance is dissolved in another.When elements or compounds that are dissolved in water leave a solution, crystallization occurs.Minerals can form in this way underground and in bodies of water.
12 Minerals from Solutions Minerals formed from evaporationDissolve salt into water = solutionAllow the water to evaporate = salt crystals left behind.Deposits of halite in ancient seas that evaporated – left crystals behind.Deposits found in Midwest, southwest, along the Gulf Coast.
13 Minerals from Solutions Minerals from Hot Water solutionsUnderground magma can heat water to high temps.Elements and compounds that form a mineral dissolve in this hot water.Water solution cools – crystals formPure metals that cool form veinsVein – a narrow channel or slab of a mineral that is different from the surrounding rockexample - Streaks of fudge in vanilla ice cream
14 What did we learn? What is crystallization? What affects the size of the crystals that form as magma cools?What are two ways that minerals form from solutions?