CHAPTER 10 Minerals and Rocks By Jamie Desrochers
Lesson 1 What are minerals? Objectives Explain what a mineral is. Name some common minerals. Identify four properties of minerals. Explain how to test the streak and hardness of a mineral. (Marshall et al, 2001)
Definition (Please enter into your notebook) Mineral -Element or compound found in the Earth’s crust (Marshall et al, 2001)
Minerals They are solids. They are formed naturally. They have the same chemical makeup throughout. They have a definite arrangement of atoms. (Marshall et al, 2001)
Common Minerals There are 3,000 different minerals Most common minerals are –Quartz –Feldspar –Mica –Calcite –Gypsum –Halite (Marshall et al, 2001)
Did you know? Quartz vibrates at a precise, constant speed when electricity passes through it. Watches use tiny bits of vibrating quartz to keep time. (Marshall et al, 2001) (The Amethysts, 2003)
Properties of Minerals Four properties can be used to identify minerals. –Color –Luster –Streak –Hardness (Marshall et al, 2001)
Color Some minerals have unique color -Sulfur is usually bright yellow Quartz may be clear, pink, black, white, or purple Color is only one clue to a mineral’s identity (Marshall et al, 2001)
Definition (Please enter into your notebook) Luster-The way a mineral reflects light (Marshall et al, 2001)
Luster There are two kinds of luster –Metallic –Nonmetallic Glassy Pearly (Marshall et al, 2001)
Common Luster Chart MineralsLuster GoldMetallic QuartzGlassy CalciteGlassy HaliteGlassy TalcPearly GarnetGlassy SilverMetallic PyriteMetallic (Marshall et al, 2001)
Definition (Please enter into your notebook) Streak -Color of the mark a mineral makes on a white tile (Marshall et al, 2001) (Yahoo image, 2005)
Definition (Please enter into your notebook) Hardness -The ability of a mineral to resist being scratched (Marshall et al, 2001)
Streak A streak test helps to identify a mineral A streak may be different then the minerals color Some minerals are so hard that they do not leave a streak (Marshall et al, 2001)
Hardness Geologist use a hardness scale from 1 to 10. The scale is called the Mohs scale. The higher the number the harder the mineral. A mineral with a higher number will scratch a lower numbered mineral. (Marshall et al, 2001)
Mohs Scale of Hardness MineralHardnessQuick Test Talc1 Easily scratch by fingernail Gypsum2 Scratch by fingernail Calcite3 Barley scratched by copper penny Fluorite4 Easily scratched by steel Apatite5 Scratched by steel Feldspar6 Scratches glass easily Quartz7 Scratches both glass and steel easily Topaz8 Scratches quartz Corundum9 No simple test Diamond10 No simple test (Marshall et al, 2001)
Self-Check (Please answer in your notebook) 1.What is a mineral? 2.Name two common minerals? 3.Why can’t color alone be used to identify minerals? 4.Why is a streak test helpful in identifying minerals? 5.The hardness of quartz is 7. The hardness of topaz is 8. Will quartz scratch topaz. Explain.
Check Your Answers 1.A naturally occurring solid, not made of living things, with a definite atomic pattern and the same chemical composition throughout. 2.Answer may vary but may include: gold, quartz, diamonds, carbon, feldspar, mica 3.Most minerals are found in more than one color, and many minerals are similar in color. 4.A mineral streak may be different then the mineral’s color. 5.No, on the Mohs hardness scale, a mineral with a higher number is harder than a mineral with a lower number. The softer mineral. Quartz will not scratch the harder mineral topaz.
Lesson 2 What are rocks? Objectives Explain what rocks are. Name and describe three main types of rocks. Describe the rock cycle. (Marshall et al, 2001)
Definition (Please enter into your notebook) Rock -Natural solid material made of one or more minerals. (Marshall et al, 2001) (Yahoo image, 2005)
Minerals make up rocks Only 20% of minerals make up 95% of rocks. Scientists who study rocks are interested in which minerals make them up and how the rocks are formed. The information helps locate valuable resources. (Marshall et al, 2001)
Definitions (Please enter into your notebook) Igneous rock -Rock formed from melted minerals the have cooled and hardened. Magma -Hot liquid rock inside the Earth. Metamorphic rock -Rock that had been changed by intense heat, pressure, and chemical reactions. Sedimentary rock -Rock formed from pieces of other rock and organic matter that was pressed and cemented together. (Marshall et al, 2001)
Three Types of Rocks Rocks are classified by how they are formed –Igneous rocks are formed from magma inside the Earth –Metamorphic rocks are formed from heat and pressure –Sedimentary rocks are formed by bits and pieces cemented together. (Marshall et al, 2001)
Rock Images Top left-sedimentary rock Top middle-metamorphic rock Top right-Igneous rock (Yahoo image, 2005)
Common Rock Chart IgneousSedimentaryMetamorphic BasaltChalkAmphibolite DioriteDolomiteGneiss GraniteFlintMarble ObsidianLimestoneMetaquartzite PumiceSandstoneSchist RhyoliteShaleslate (Marshall et al, 2001)
Definition (Please enter into your notebook) Rock Cycle – Series of changes through which one kind of rock becomes another kind of rock. (Marshall et al, 2001)
The Rock Cycle Magma rises, cools, and hardens into igneous rock. It rises to the surface breaks apart, forming sediment. Sediment is carried to the ocean by rivers were it builds up and becomes sedimentary rock. Heat and pressure change it into metamorphic rock. The rock cycle can have many other paths. (The Rock Cycle, 1997)
Self-Check (Please answer in your notebook) 1.What is a rock? 2.What are the three main types of rocks? 3.Which type of rock is granite? 4.How do metamorphic rocks form? 5.Explain the rock cycle.
Check Your Work 1.A natural solid material made of one or more minerals 2.Igneous, sedimentary, and metamorphic rocks 3.Igneous 4.Heat, pressure, and hot fluids change the appearance and texture of preexisting rock to form metamorphic rocks. 5.A series of changes that rocks undergo as they change into other rocks.
Quiz (Please answer in your notebook) What are four features that all minerals have in common? What is a rock? How do scientist use information about rocks? Name the three types of rock and describe how each type if formed? Describe how the “quick test” is used to estimate a mineral’s hardness.
FYI For more information about rocks and minerals please check out the following websites. The Mineral Gallery http://www.fi.edu/tfi/units/rocks/rocks.html Rocks and Mineral Slide Show http://volcano.und.nodak.edu/.../vwlessons/lessons/Slideshow/Slideinex.html Rock and Mineral Web Quest http://cte.jhu.edu/techacademy/fellows/brannon/webquest/kmbindex.html Rock and Mineral Links http://edtech.kennesaw.edu/web/rocks.html
References Center for Educational Technology, (1997). The rock cycle. retrieved Jan. 22, 2005, from Earth's Cycles Web site: http://ww.cotf.edu/ete/modules/msese/earthsysflr/rock.html http://ww.cotf.edu/ete/modules/msese/earthsysflr/rock.html Marshall, R., Jacobs, D., Rosskopf, A., & LaRue, C. (2001). General science. Circle Pines, MN: American Guidance Service. Yahoo image. (2005). retrieved Jan. 22, 2005, from Rock imagin Web site: http://images.search.yahoo.com/search/images http://images.search.yahoo.com/search/images The Amethyst. (2003). Retrieved February 8, 2005) from Amethyst web site: http://mineral.galleries.com/minerals/silicate/quartz/quart http://mineral.galleries.com/minerals/silicate/quartz/quart