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Unit 3 Minerals and Rocks
The Big Idea: Minerals and rocks are basic building blocks of Earth and can change over time from one type of mineral or rock to another
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Animal, Vegetable, or Mineral?
Unit 3 Lesson 1 Minerals Mineral-a naturally occurring, inorganic solid with a definite crystalline structure and chemical composition. Elements- pure substances that cannot be broken down into simpler substances by chemical means. Atom-building block of matter, each element is made up of one kind Compound- A substance made up of molecules of two or more elements Not all minerals are sparkling gems, but they all have certain characteristics in common. Stable particles that are made up of strongly bonded atoms are called molecules. The chemical composition of a mineral is determined by the element or compound that makes up the mineral. A mineral composed of only one element is called a native element. In the mineral quartz, each silicon atom forms a bond with up to four oxygen atoms.
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What’s the Matter with you?
Unit 3 Lesson 1 Minerals What’s the Matter with you? Matter- anything that has mass and volume. Volume-amount of space something takes up. All minerals are solid, meaning each has a definite volume and shape. All minerals are inorganic, which means they are not produced by living things or from the remains of living things. All minerals are naturally occurring.
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They can form from any of the following:
Unit 3 Lesson 1 Minerals Crystals- solid geometric forms produced by a repeating pattern of atoms or molecules. They can form from any of the following: magma –change from liquid to solid lava metamorphism- P & T chemical makeup; no melting Solutions-like water The type of mineral that forms depends on the elements present in the area and the temperature and pressure. Many minerals form from magma, which is molten rock inside Earth. As magma cools, the atoms join together to form different minerals. Minerals also form from lava, which is molten rock that has reached Earth’s surface. Many minerals form by metamorphism. ON THE TEST High temperature and pressure within Earth cause new minerals to form (chemical makeup)as bonds between atoms break and reform with different atoms. Minerals also form from solutions. Water usually has substances dissolved in it. As it evaporates, these substances form into solids and come out of solution, or precipitate. As hot water cools, dissolved substances may precipitate out of solution.
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Silicate- combination of Si and O. 90% of earth’s crust
Unit 3 Lesson 1 Minerals Sort It Out Silicate- combination of Si and O. 90% of earth’s crust Nonsilicate – some are made of C, O, F, Fe, & S. Classes of Nonsilicates (see page 147) Native elements-made of only 1 element Halides Sulfates Carbonates Oxides Sulfides Most silicate minerals are formed from silicate tetrahedrons, each made of one silicon atom bonded to four oxygen atoms. Nonsilicate minerals are minerals that do not contain the silicate tetrahedron building block. Copyright © Houghton Mifflin Harcourt Publishing Company 5
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Properties of minerals
Unit 3 Lesson 1 Minerals Name That Mineral! Properties of minerals Color Streak Luster-light reflection Cleavage-split along planes of weakness to form smooth, flat surfaces Density Hardness-resistance to being scratched Magnetism Color-is helpful, but not the best way to identify a mineral. The color of the powdered form of a mineral is its streak, found by rubbing it against a white tile streak plate. The way a surface reflects light is called luster. Two major types of luster are metallic and nonmetallic. A mineral with cleavage breaks along flat surfaces that generally run parallel to planes of weakness in the crystal structure. Minerals that don’t have cleavage will fracture, or break unevenly, along curved or jagged surfaces. Density, which is the amount of matter in a given amount of space, can be used to tell many similar-looking minerals apart. A mineral’s resistance to being scratched is called its hardness. Mineral hardness is compared using the Mohs hardness scale. A few minerals exhibit special properties such as magnetism. Many useful substances come from minerals. The metal titanium comes from several minerals, including rutile. Titanium is very valuable because it resists corrosion and is as strong as steel, but is much lighter than steel. Titanium is used for surgical devices because it resists corrosion and has elasticity similar to human bone. Titanium dissipates heat, making it ideal for exhaust pipes. Titanium is also valued for its shiny metallic luster, so it has also been used in architectural designs. 6
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Texture- size, shape & positions of grains
Rock-combination of 1 or more minerals or organic matter, can be made of noncrystalline material Rock Classification Composition – makeup Texture- size, shape & positions of grains
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Classified Information!
Unit 3 Lesson 2 The Rock Cycle Classified Information! Igneous rock- forms when magma cools and hardens. It forms on or beneath Earth’s surface. Intrusive- magma intrudes, or pushes into surrounding rock below Earth’s surface, and cools. (i.e. course grain texture) Extrusive-when lava erupts, or extrudes, onto Earth’s surface (i.e. fine grain texture) Magma is molten rock that forms in Earth’s crust. When magma cools and solidifies, it forms igneous rock in the crust. Magma that reaches Earth’s surface is called lava. Igneous rock also forms when lava cools and solidifies on Earth’s surface. The magma usually cools very slowly, and the minerals form large, visible crystals. Therefore, intrusive igneous rock generally has a coarse-grained texture. Igneous rock that forms when lava erupts, or extrudes, onto Earth’s surface is called extrusive igneous rock. As lava cools quickly, there is little time for crystals to form, and extrusive igneous rocks have a fine-grained texture. Obsidian, often called volcanic glass, is an extrusive rock that cools so rapidly that no crystals form. 9
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Unit 3 Lesson 3 Three Classes of Rock
Lay It On! Sedimentary rock- forms when sediment from older rocks or minerals that form from solutions get pressed and cemented together. Formed by the following processes Weathering Erosion Deposition Burial Cementation. Copyright © Houghton Mifflin Harcourt Publishing Company
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Sedimentary Classifications
Clastic –buried, compacted & cemented together by calcite or quartz (conglomerate, sandstone, shale, and siltstone) Chemical-forms when water, which usually contains dissolved minerals, evaportes (rock salt, flint, iron ore) Organic-forms from the remains, or fossils, of once-living plants & animals (limestone, coal, oil shale) Clastic sedimentary rock forms when sediments are buried, compacted, and cemented together by calcite or quartz. i.e. conglomerate, sandstone, shale, and siltstone The size of the sediment, or clasts, that makes up the rock is used to classify clastic sedimentary rocks as fine-, medium-, or coarse-grained. Chemical sedimentary rock forms when water, which usually contains dissolved minerals, evaporates. i.e. rock salt, flint, iron ore As water evaporates, the minerals in it become concentrated, precipitate out of solution, and crystallize. Organic sedimentary rock forms from the remains, or fossils, of once-living plants and animals. i.e. limestone, coal, oil shale Over time, the skeletons of marine organisms, made of calcium carbonate, collect on the ocean floor. These animal remains, together with sediment, are eventually buried, compacted, and cemented together to form fossiliferous limestone.
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Unit 3 Lesson 3 Three Classes of Rock
The Heat Is On! Metamorphic rock-forms when pressure, temperature, or chemical processes change existing rock. Foliated- occurs when pressure causes the mineral grains in a rock to realign to form parallel bands Nonfoliated – do not have mineral grains that are aligned in planes or bands As a rock is exposed to high temperature and pressure, the crystal structures of the minerals in the rock change to form new minerals. The metamorphic rock texture in which mineral grains are arranged in planes or bands is called foliation. Nonfoliated metamorphic rocks are commonly made of one or only a few minerals. During metamorphism, mineral grains or crystals may change in size or the mineral may change in composition.
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Unit 3 Lesson 2 The Rock Cycle
The minerals a rock contains determine the composition, or makeup, of that rock. The size, shape, and positions of the grains that make up a rock determine a rock’s texture. The rock may be coarse-grained or fine-grained, depending on whether the grains are visible with one’s eyes or with a hand lens or microscope. Draw on the picture the same as pages Factors of change include temperature, pressure, weathering and erosion 13
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