Rocks and Minerals

1. Rocks and Minerals

2. Quartz Apatite Diamond hardness color Topaz fracture Gypsum talc Minerals luster Corundum density Orthoclase Calcite Fluorite cleavage

3. EQ: What is a mineral? Standard: S6E5.b Investigate the contribution of minerals to rock composition.

4. What are the characteristics of a mineral? How are minerals identified? What is the Mohs hardness scale? What is the major difference between an element and a compound? EQ: How are minerals identified?

5. Properties of Minerals • A mineral is a naturally formed, inorganic solid that has a crystal structure and a definite chemical composition. • Each mineral has its own set of specific physical properties that can be used to identify it (hardness, color, streak, luster, density, crystal system, cleavage and fracture). • An element is a substance composed of a singlekind of atom. • A compound is two or more elements combined so that the elements no longer have their original distinct properties.

6. Properties of Minerals • Naturally Formed- must form naturally • Inorganic- cannot arise from materials that were once part of a living thing • Solid- always solid, with a definite volume and a definite shape • Crystalline Structure- particles must line up in a pattern that repeats over and over again • Definite Chemical Composition- always contains certain elements in definite proportions. NaCl (salt)

7. Identifying Minerals • Hardness- Mohs hardness scale ranks ten minerals from softest to hardest. • Color- Because of factors, such as impurities, used only to identify a few minerals • Streak- the color of a mineral in its powdered form • Luster- how a mineral reflects light from its surface • Density- the ratio of the mass to the volume of a substance • Crystal Systems- six groups of structures based on the number and angle of the crystal faces • Cleavage – splitting along smooth, flat surface • Fracture- breaking apart along curved or irregular surfaces

8. Special Properties • Some properties are particular to only a few types of minerals: • Fluorescence – glow under ultraviolet light • Chemical Reactions – reacts to an acid • Magnetism – natural magnets that attract iron. • Taste – ex. Halite has a salty taste • Optical Properties – some can cause a double image • Radioactivity – minerals that contain radium or uranium

9. Mohs Hardness Scale • Talc 1 Softest known mineral • Gypsum 2 fingernail can scratch it • Calcite 3 scratched by copper penny • Fluorite 4 easily scratched by steel knife • Apatite 5 can be scratched by steel knife • Orthoclase 6 can scratch window glass • Quartz 7 can scratch steel • Topaz 8 can scratch quartz • Corundum 9 can scratch topaz • Diamond 10 hardest known mineral

10. Quick Check • 1. Which of the following is NOT a characteristic of a mineral? • It is formed in nature. • It is a living material. • It has a crystalline structure. • It is a solid.

11. Quick Check • 2. Which of the following properties of minerals does Mohs scale measure? • luster • density • hardness • streak

12. Quick Check • 3. Pure substances cannot be broken down into simpler substances by ordinary chemical means are called a. molecules. b. compounds. c. crystals. d. elements.

13. Quick Check • 4. Which of the following properties is considered a special property that applies to only a few minerals? a. luster b. taste c. hardness d. density

14. Quick Check • 5. Which of the following substances is a mineral? a. fluorite, which is a crystalline solid with the chemical formula CaF2 b. coal, which forms from the remains of living things. c. obsidian, which is a volcanic glass and is not crystalline. d. brass, which is a metal that is made by humans.

15. What is a crystal, and what determines a crystal’s shape? Describe the two major groups of minerals. What is a native element? EQ: What is a mineral?

16. Mineral Structure • A mineral is a naturally formed, inorganic solid that has a define crystalline structure. • Minerals may be either elements or compounds. • Elements are pure substances that cannot be broken down into simpler substances by ordinary means. • A compoundis a substance made of two or more elements that have been chemically joined together. • A mineral that is composed of only one element is called a native element.

17. Crystals • A crystal is a solid whose atoms, ions, or molecules are arranged in a definite pattern. • Crystals are solid, geometric forms produced by a repeating pattern of atoms or molecules that are present throughout the mineral. • A crystal’s shape is determined by thearrangement of the atoms or molecules within the crystal. • All minerals can be grouped into crystal classes according to the kinds of crystals they form.

18. Two Groups of Minerals • Minerals are divided into two groupsbased on their chemical composition. • Silicate minerals are minerals that contain a combination of the elements silicon and oxygen (quartz, feldspar, mica). • Silicate minerals make up over 90% of the Earth’s crust. • Nonsilicate minerals are minerals that do not contain a combination of the elements silicon and oxygen ( copper, calcite, fluorite, corundum, gypsum, galena).

19. Quick Check • 1. What are the two major groups of minerals? • metallic and nonmetallic • native elements and carbonates • silicates and nonsilicates • quartz and mica

20. Quick Check • 2. Silicate minerals contain a combination of the elements • Sulfur and oxygen. • Carbon and oxygen. • Iron and oxygen. • Silicon and oxygen.

21. Quick Check • 3. Which of the following is a nonsilicate mineral? • orthoclase, KASi3O8 • Talc, Mg3Si4O10(OH)2 • Almandine, Fe3Al2(SiO4)3 • Magnetite, Fe3O4

22. Where can you find minerals? What is an ore? Compare surface and subsurface mining. What is reclamation? What are some examples of minerals and their uses? The Formation, Mining, and Use of Minerals (p.74)

23. The Formation of Minerals • Minerals form in a variety of environments in Earth’s crust. • Each of these environments has a different set of physical and chemical conditions. • The environment in which a mineral forms determines the mineral’s properties. • Environments in which minerals form may be on or near Earth’s surface or deep beneath Earth’s surface.

24. The Environments Evaporating Salt Water • When a body of salt water dries up, minerals are left behind. -gypsum, halite Metamorphic Rocks • When changes in temperature, pressure, or chemical make-up changes a rock, metamorphism takes place. • -calcite, garnet, graphite, hematite, magnetite, mica, and talc

25. The Environments Limestones • Surface water and ground water carry dissolved materials to lakes and seas where they crystallize on the bottom -Calcite, dolomite Hot-Water Solutions • Groundwater works its way downward and is heated by magma. It then reacts with minerals to form a hot liquid solution. -gold, copper, sulfur, pyrite, galena

26. The Environments Pegmatites • As magma moves upward, it can form teardrop-shaped bodies called pegmatites. The mineral crystals become extremely large. -many gemstones, such as topaz, tourmaline Plutons • As magma rises upward through the crust, it sometimes stops moving before it reaches the surface and cools slowly, forming millions of mineral crystals. The entire magma body solidifies to form a pluton. • Mica, feldspar, magnetite, quartz

27. Mining • An ore is the natural material large enough and pure enough to be mined for profit. • Rocks and minerals are removed from the ground by one of two methods-surface mining and subsurface mining. • Surface mining is used to remove mineral deposits on or near the Earth’s surface. - open pits - surface coal mines (open-pit) - quarries

28. Mining • Subsurface mining is used when mineral deposits are located too deep within Earth to be surface mined. • Mine reclamation is the process by which land used for mining is returned to its original state or better. • Has been required by law since the mid-1970’s. • To reduce the effects of mining, reduce our need for minerals. • Recycle!

29. The Use of Minerals • Some minerals are of major economic and industrial importance. • Metallic minerals have shiny surfaces, do not let light pass through them, good conductors of heat and electricity. • Nonmetallic minerals have shiny or dull surfaces, may let light pass through them, and are good insulators of electricity.

30. The Use of Minerals • Gemstones are highly valuable minerals because of their beauty and rarity rather than their usefulness. • Color is the most important characteristic of a gemstone. • The more attractive the color is, the more valuable the gem is. • Mass of a gem is expressed in a unit known as a carat. • One carat is equal to 200 mg.

31. Common Uses of Minerals

32. Quick Check • In a mineral, the particles line up in a repeating pattern to form • A. an element • B. a crystal • C. a mixture • D. a compound

33. Quick Check • The term that describes how a mineral reflects light is its __________. • A. luster. • B. streak • C. color. • D. weight.

34. Quick Check • One characteristic that a substance must have to be considered a mineral is _____. • A. to be living. • B. to be small. • C. to a liquid. • D. to be a solid.

35. Quick check • A compound is two or more ________ chemically combined. • A. atoms • B. minerals • C. elements • D. protons

36. Quick Check • An element is a substance composed of a single kind of __________. • A. compound. • B. atom. • C. mineral. • D. Mohs hardness scale.

37. Quick Check • The groupings silicate and nonsilicate minerals are based on • Organic content. • Gas and liquid state • Chemical composition. • Color.

38. Quick Check • Nonsilicate minerals • Do not contain oxygen. • Include native elements. • All have a nonmetallic luster. • Are all rare substances.

39. Quick Check Which of the following is NOT a class of nonsilicate minerals? • oxides • Micas • carbonates • native elements

40. Quick Check What is a mineral deposit that is large and pure enough to be mined called? • gemstone • ore • pluton • pegmatite

41. Quick Check Halides form when fluorine, chlorine, or bromine combine with any of the following elements EXCEPT • sodium. • potassium. • calcium. • oxygen.

42. Quick Check • What is the name for nonmetallic minerals that are valued for their beauty and rarity rather than their usefulness? • plutons • gemstones • ores • pegmaites

43. Quick Check • What kinds of mines are open pit and quarry mines? • shaft mines • slope mines • surface mines • subsurface mines

44. ROCK: Mineral Mixtures sediments cooling sedimentary melting erosion magma igneous pressure lava metamorphic cementation heat

45. EQ: How are rocks formed? Standard S6E5.c Classify rocks by their process of formation.

46. How are rocks classified? How does igneous rock become sedimentary rock? How does sedimentary rock become metamorphic rock? How does metamorphic rock become igneous rock? How are rocks classified?

47. Rock Formation • Scientists classify rocks by the way they are formed. • Rocks are composed of minerals and other materials. • Minerals are the building blocks of rocks. • Rocks are classified into three (3) groups based on how they are formed: • Sedimentary rocks • Igneous rocks • Metamorphic rocks

48. What materials are rocks made of? Describe four processes that change rock from one type to another. What are the three main classes of rock? Describe two characteristics of rock that are used to help classify it. The Rock Cycle

49. What materials are rocks made of? • Rock is describe as a naturally occurring solid mixture of one or more minerals and organic matter. • Rocks are made of mixtures of minerals and other materials, although some rocks may contain only a single mineral. When studying a rock sample, geologists observe the rock’s color and texture and determine its mineral composition. • Texture is described with terms based on grain size, grain shape, and grain pattern. Most rocks are made up of tiny particles of minerals or other rocks, which are called grains. A rock’s grains give it its texture. • There are three major groups of rocks: igneous rock, sedimentary rock, and metamorphic rock. These terms refer to how the rocks in each group were formed.

50. The Rock Cycle • The rock cycle is a series of processes in which a rock forms, changes from one type to another, is destroyed, and forms again by geological processes. • Rocks have been used by humans to make tools and weapons and to construct buildings.