Chapter 3: Minerals · 2011. 4. 6. · minerals. A mineral is a naturally occurring, inorganic solid with a definite chemical composition and an orderly arrange-ment of atoms. About

sections

1 MineralsLab Crystal Formation

2 Mineral Identification

3 Uses of MineralsLab Mineral Identification

Virtual Lab How canminerals be defined bytheir properties?

Nature’s Beautiful CreationAlthough cut by gemologists to enhancetheir beauty, these gorgeous diamondsformed naturally—deep within Earth. Onerequirement for a substance to be a mineralis that it must occur in nature. Human-made diamonds serve their purpose inindustry but are not considered minerals.

Write two questions you would aska gemologist about the minerals that he or she works with.Science Journal

Minerals

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61

Minerals Make the followingFoldable to help you betterunderstand minerals.

Fold a verticalsheet of note-book paper fromside to side.

Cut along every third line of only thetop layer to form tabs.

Label each tab with a question.

Ask Questions Before you read the chapter,write questions you have about minerals on thefront of the tabs. As you read the chapter, addmore questions and write answers under theappropriate tabs.

STEP 3

STEP 2

STEP 1

1. Use a magnifying lens to observe aquartz crystal, salt grains, and samplesof sandstone, granite, calcite, mica, andschist (SHIHST).

2. Draw a sketch of each sample.

3. Infer which samples are made of one typeof material and should be classified asminerals.

4. Infer which samples should be classifiedas rocks.

5. Think Critically In your Science Journal,compile a list of descriptions for the min-erals you examined and a second list ofdescriptions for the rocks. Compare andcontrast your observations of mineralsand rocks.

Distinguish Rocks from MineralsWhen examining rocks, you’ll notice thatmany of them are made of more than onematerial. Some rocks are made of many dif-ferent crystals of mostly the same mineral.A mineral, however, will appear more like apure substance and will tend to look thesame throughout. Can you tell a rock from amineral?

Start-Up Activities

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62 CHAPTER 3 Minerals

What is a mineral?How important are minerals to you? Very important? You

actually own or encounter many things made from mineralsevery day. Ceramic, metallic, and even some paper items areexamples of products that are derived from or include minerals.Figure 1 shows just a few of these things. Metal bicycle racks,bricks, and the glass in windows would not exist if it weren’t forminerals. A mineral is a naturally occurring, inorganic solidwith a definite chemical composition and an orderly arrange-ment of atoms. About 4,000 different minerals are found onEarth, but they all share these four characteristics.

Mineral Characteristics First, all minerals are formed bynatural processes. These are processes that occur on or insideEarth with no input from humans. For example, salt formed bythe natural evaporation of seawater is the mineral halite, but saltformed by evaporation of saltwater solutions in laboratories isnot a mineral. Second, minerals are inorganic. This means thatthey aren’t made by life processes. Third, every mineral is an ele-ment or compound with a definite chemical composition. Forexample, halite’s composition, NaCl, gives it a distinctive taste thatadds flavor to many foods. Fourth, minerals are crystalline solids.All solids have a definite volume and shape. Gases and liquids likeair and water have no definite shape, and they aren’t crystalline.Only a solid can be a mineral, but not all solids are minerals.

Atom Patterns The wordcrystalline means that atoms arearranged in a pattern that isrepeated over and over again. Forexample, graphite’s atoms arearranged in layers. Opal, on theother hand, is not a mineral inthe strictest sense because itsatoms are not all arranged in adefinite, repeating pattern, eventhough it is a naturally occur-ring, inorganic solid.

■ Describe characteristics that allminerals share.

■ Explain how minerals form.

You use minerals and productsmade from them every day.

Review Vocabularyatoms: tiny particles that makeup matter; composed of protons,electrons, and neutrons

New Vocabulary

• mineral • magma• crystal • silicate

Minerals

Figure 1 You probably useminerals or materials made fromminerals every day without think-ing about it.Infer How many objects in this pic-ture might be made from minerals?

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SECTION 1 Minerals 63

The Structure of Minerals Do you have a favorite mineral sample or gemstone? If so,

perhaps it contains well-formed crystals. A crystal is a solid inwhich the atoms are arranged in orderly, repeating patterns.You can see evidence for this orderly arrangement of atomswhen you observe the smooth, flat outside surfaces of crystals. Acrystal system is a group of crystals that have similar atomicarrangements and therefore similar external crystal shapes.

What is a crystal?

Crystals Not all mineral crystals have smooth surfaces andregular shapes like the clear quartz crystals in Figure 2. The rosequartz in the smaller photo of Figure 2 has atoms arranged inrepeating patterns, but you can’t see the crystal shape on the out-side of the mineral. This is because the rose quartz crystals devel-oped in a tight space, while the clear quartz crystals developedfreely in an open space. The six-sided, or hexagonal crystal shapeof the clear quartz crystals in Figure 2, and other forms of quartzcan be seen in some samples of the mineral. Figure 3 illustratesthe six major crystal systems, which classify minerals accordingto their crystal structures. The hexagonal system to which quartzbelongs is one example of a crystal system.

Crystals form by many processes. Next, you’ll learn abouttwo of these processes—crystals that form from magma andcrystals that form from solutions of salts.

Figure 2 More than 200 years ago,the smooth, flat surfaces on crystalsled scientists to infer that mineralshad an orderly structure inside.

Even though this rose quartzlooks uneven on the outside,its atoms have an orderlyarrangement on the inside.

The well-formed crystal shapesexhibited by these clear quartzcrystals suggest an orderly structure.

Inferring Salt’sCrystal SystemProcedure1. Use a magnifying lens to

observe grains of commontable salt on a dark sheetof construction paper.Sketch the shape of a saltgrain. WARNING: Donot taste or eat mineralsamples. Keep hands awayfrom your face.

2. Compare the shapes ofthe salt crystals with theshapes of crystals shown inFigure 3.

Analysis1. Which characteristics do all

the grains have in common?2. Research another mineral

with the same crystal sys-tem as salt. What is thiscrystal systemcalled?

(inset)John R. Foster/Photo Researchers, (l)Mark A. Schneider/Visuals Unlimited

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Figure 3

VISUALIZING CRYSTAL SYSTEMS


A crystal’s shape depends on how its atoms are arranged.Crystal shapes can be organized into groups known as crys-tal systems—shown here in 3-D with geometric models(in blue). Knowing a mineral’s crystal system helps researchersunderstand its atomic structure and physical properties.

TETRAGONAL (te TRA guh nul)Zircon crystals are tetragonal.Tetra-gonal crystals are much like cubiccrystals, except that one of the princi-pal dimensions is longer or shorterthan the other two dimensions.

TRICLINIC (tri KLIH nihk) Thetriclinic crystal system includesminerals exhibiting the leastsymmetry.Triclinic crystals, suchas rhodonite (ROH dun ite),are unequal in all dimensions,and all angles where crystal surfaces meet are oblique.

MONOCLINIC (mah nuh KLIH nihk)Minerals in the monoclinic system,such as orthoclase, also exhibit unequaldimensions in their crystal structure.Only one right angle forms where crystal surfaces meet.The other anglesare oblique, which means they don’tform 90º angles where they intersect.

HEXAGONAL (hek SA guh nul) In hexag-onal crystals, horizontal distances betweenopposite crystal surfaces are equal.Thesecrystal surfaces intersect to form 60º or120º angles.The vertical length is longer orshorter than the horizontal lengths.

CUBIC Fluorite is anexample of a mineralthat forms cubic crystals.Minerals in the cubiccrystal system are equalin size along all threeprincipal dimensions.

ORTHORHOMBIC(awr thuh RAHM bihk)Minerals with orthorhombicstructure, such as barite, havedimensions that are unequalin length, resulting in crystalswith a brick-like shape.

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SECTION 1 Minerals 65

Crystals from Magma Natural processes form minerals inmany ways. For example, hot melted rock material, calledmagma, cools when it reaches Earth’s surface, or even if it’strapped below the surface. As magma cools, its atoms lose heatenergy, move closer together, and begin to combine into com-pounds. During this process, atoms of the different compoundsarrange themselves into orderly, repeating patterns. The typeand amount of elements present in a magma partly determinewhich minerals will form. Also, the size of the crystals that formdepends partly on how rapidly the magma cools.

When magma cools slowly, the crystals that form are gener-ally large enough to see with the unaided eye, as shown inFigure 4A. This is because the atoms have enough time to movetogether and form into larger crystals. When magma cools rap-idly, the crystals that form will be small. In such cases, you can’teasily see individual mineral crystals.

Crystals from Solution Crystals also can form from miner-als dissolved in water. When water evaporates, as in a dry climate,ions that are left behind can come together to form crystals likethe halite crystals in Figure 4B. Or, if too much of a substance isdissolved in water, ions can come together and crystals of thatsubstance can begin to form in the solution. Minerals can formfrom a solution in this way without the need for evaporation.

Some minerals form when saltwater evaporates, such as thesewhite crystals of halite in DeathValley, California.

Labradorite

Crystal FormationEvaporites commonlyform in dry climates.Research the changesthat take place when asaline lake or shallow seaevaporates and haliteor gypsum forms.

Figure 4 Minerals form bymany natural processes.

This rock formed as magmacooled slowly, allowing largemineral grains to form.

(inset)Patricia K. Armstrong/Visuals Unlimited, (r)Dennis Flaherty Photography/Photo Researchers

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Self Check1. List four characteristics that all minerals share.

2. Describe two ways that minerals can form from solution.

3. Explain whether diamonds made in the laboratory areconsidered to be minerals.

4. Describe how crystals of minerals are classified.

5. Think Critically The mineral dolomite, a rock-formingmineral, contains oxygen, carbon, magnesium, andcalcium. Is dolomite a silicate? Explain.

SummaryWhat is a mineral?

• Many products used by humans are madefrom minerals.

• Minerals are defined by four maincharacteristics.

The Structure of Minerals

• The crystal shape of a mineral reflects the wayin which its atoms are arranged.

• Minerals are classified according to the typesof atoms in their structures and the way thatthe atoms are arranged.

Mineral Compositions and Groups

• Only eight elements form approximately98 percent (by weight) of Earth’s crust.

• The majority of Earth’s crust is composed ofsilicate minerals.

6. Graph Make a graph of your own design that showsthe relative percentages of the eight most commonelements in Earth’s crust. Then determine theapproximate percentage of the crust that is made upof iron and aluminum. If one is available, you mayuse an electronic spreadsheet program to make your graph and perform the calculation.

Mineral Compositionsand Groups

Ninety elements occur naturally in Earth’scrust. Approximately 98 percent (by weight)of the crust is made of only eight of these ele-ments, as shown in Figure 5. Of the thou-sands of known minerals, only a few dozenare common, and these are mostly composedof the eight most common elements inEarth’s crust.

Most of the common rock-formingminerals belong to a group called the sili-cates. Silicates (SIH luh kayts) are mineralsthat contain silicon (Si) and oxygen (O) andusually one or more other elements. Silicon

and oxygen are the two most abundant elements in Earth’scrust. These two elements alone combine to form the basicbuilding blocks of most of the minerals in Earth’s crust andmantle. Feldspar and quartz, which are silicates, and calcite,which is a carbonate, are examples of common, rock-formingminerals. Other mineral groups also are defined according totheir compositions.

Elements in Earth’s CrustPe

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un

dan

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46.6%

27.7%

8.1%5.0% 3.6% 2.8% 2.6% 2.1% 1.5%

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Figure 5 Most of Earth’s crust iscomposed of eight elements.

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In this lab, you’ll have a chance to learn howcrystals form from solutions.

Real-World QuestionHow do crystals form from solution?

Goals■ Compare and contrast the crystals that

form from salt and sugar solutions.■ Observe crystals and infer how they formed.

Materials250-mL beakers (2) cotton stringcardboard hot platelarge paper clip magnifying lenstable salt thermal mittflat wooden stick shallow pangranulated sugar spoon

Safety Precautions

WARNING: Never taste or eat any lab materials.

Procedure1. Gently mix separate solutions of salt in

water and sugar in water in the twobeakers. Keep stirring the solutions as youadd salt or sugar to the water. Stop mixingwhen no more salt or sugar will dissolve inthe solutions. Label each beaker.

2. Place the sugar solution beaker on a hotplate. Use the hot plate to heat the sugarsolution gently. WARNING: Do not touch thehot beaker without protecting your hands.

3. Tie one end of the thread to the middle of thewooden stick. Tie a large paper clip to thefree end of the string for weight. Place thestick across the opening of the sugar beaker

so the thread dangles in the sugar solution.

4. Remove the beaker from the hot plate andcover it with cardboard. Place it in a locationwhere it won’t be disturbed.

5. Pour a thin layer of the salt solution into theshallow pan.

6. Leave the beaker and the shallow panundisturbed for at least one week.

7. After one week, examine each solution witha magnifying lens to see whether crystalshave formed.

Conclude and Apply1. Compare and contrast the crystals that

formed from the salt and the sugar solu-tions. How do they compare with samples oftable salt and sugar?

2. Describe what happened to the saltwatersolution in the shallow pan.

3. Did this same process occur in the sugarsolution? Explain.

Crystal Formation

Make a poster that describes your methodsof growing salt and sugar crystals. Presentyour results to your class.

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Physical PropertiesWhy can you recognize a classmate when you see him or her

in a crowd away from school? A person’s height or the shape ofhis or her face helps you tell that person from the rest of yourclass. Height and facial shape are two properties unique to indi-viduals. Individual minerals also have unique properties thatdistinguish them.

Mineral Appearance Just like height and facial characteris-tics help you recognize someone, mineral properties can helpyou recognize and distinguish minerals. Color and appearanceare two obvious clues that can be used to identify minerals.

However, these clues alone aren’t enough to recognize mostminerals. The minerals pyrite and gold are gold in color and canappear similar, as shown in Figure 6. As a matter of fact, pyriteoften is called fool’s gold. Gold is worth a lot of money, whereaspyrite has little value. You need to look at other properties ofminerals to tell them apart. Some other properties to studyinclude how hard a mineral is, how it breaks, and its color whencrushed into a powder. Every property you observe in a mineralis a clue to its identity.

■ Describe physical propertiesused to identify minerals.

■ Identify minerals using physicalproperties such as hardness andstreak.

Identifying minerals helps you rec-ognize valuable mineral resources.

Review Vocabularyphysical property: any character-istic of a material that you canobserve without changing theidentity of the material

New Vocabulary

• hardness • streak• luster • cleavage• specific gravity • fracture

Mineral Identification

Using only color, observers can be fooled when trying todistinguish between pyrite and gold.

The mineral azurite is identifiedreadily by its striking blue color.

Gold

Pyrite Azurite

Figure 6 The generalappearance of a mineral oftenis not enough to identify it.

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SECTION 2 Mineral Identification 69

Hardness A measure of how easily a mineral can bescratched is its hardness. The mineral talc is so softyou can scratch it loose with your fingernail. Talcumpowder is made from this soft mineral. Diamonds, onthe other hand, are the hardest mineral. Some dia-monds are used as cutting tools, as shown in Figure 7.A diamond can be scratched only by another dia-mond. Diamonds can be broken, however.

Why is hardness sometimes referredto as scratchability?

Sometimes the concept of hardness is confused with whetheror not a mineral will break. It is important to understand thateven though a diamond is extremely hard, it can shatter if givena hard enough blow in the right direction along the crystal.

Mohs Scale In 1824, the Austrian scientist Friedrich Mohsdeveloped a list of common minerals to compare their hard-nesses. This list is called Mohs scale of hardness, as seen in Table 1. The scale lists the hardness of ten minerals. Talc, the soft-est mineral, has a hardness value of one, and diamond, the hard-est mineral, has a value of ten.

Here’s how the scale works.Imagine that you have a clear orwhitish-colored mineral that youknow is either fluorite or quartz.You try to scratch it with your fin-gernail and then with an iron nail.You can’t scratch it with your fin-gernail but you can scratch it withthe iron nail. Because the hard-ness of your fingernail is 2.5 andthat of the iron nail is 4.5, you candetermine the unknown mineral’shardness to be somewhere around3 or 4. Because it is known thatquartz has a hardness of 7 andfluorite has a hardness of 4, themystery mineral must be fluorite.

Some minerals have a hard-ness range rather than a singlehardness value. This is becauseatoms are arranged differently indifferent directions in their crystalstructures.

Figure 7 Some saw blades havediamonds embedded in them tohelp slice through materials, suchas this limestone. Blades are keptcool by running water over them.

Table 1 Mineral Hardness

Mohs Hardness

Hardness ofScale Common Objects

Talc (softest) 1

Gypsum 2 fingernail (2.5)

Calcite 3 piece of copper (2.5 to 3.0)

Fluorite 4 iron nail (4.5)

Apatite 5 glass (5.5)

Feldspar 6 steel file (6.5)

Quartz 7 streak plate (7.0)

Topaz 8

Corundum 9

Diamond (hardest) 10

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Luster The way a mineral reflects light is knownas luster. Luster can be metallic or nonmetallic.Minerals with a metallic luster, like the graphiteshown in Figure 8, shine like metal. Metallic lustercan be compared to the shine of a metal belt buckle,the shiny chrome trim on some cars, or the shine ofmetallic cooking utensils. When a mineral does notshine like metal, its luster is nonmetallic. Examples ofterms for nonmetallic luster include dull, pearly,silky, and glassy. Common examples of minerals withglassy luster are quartz, calcite, halite, and fluorite.

Specific Gravity Minerals also can be distinguished by com-paring the weights of equal-sized samples. The specific gravity ofa mineral is the ratio of its weight compared with the weight of anequal volume of water. Like hardness, specific gravity is expressedas a number. If you were to research the specific gravities of goldand pyrite, you’d find that gold’s specific gravity is about 19, andpyrite’s is 5. This means that gold is about 19 times heavier thanwater and pyrite is 5 times heavier than water. You could experi-ence this by comparing equal-sized samples of gold and pyrite inyour hands—the pyrite would feel much lighter. The term heft issometimes used to describe how heavy a mineral sample feels.

Figure 8 Luster is an importantphysical property that is used todistinguish minerals. Graphite hasa metallic luster. Fluorite has anonmetallic, glassy luster.

How can you identify minerals?

You have learned that minerals are identi-fied by their physical properties, such asstreak, hardness, cleavage, and color. Useyour knowledge of mineral properties andyour ability to read a table to solve the fol-lowing problems.

Identifying the Problem The table includes hardnesses and streak

colors for several minerals. How can you usethese data to distinguish minerals?

Solving the Problem 1. What test would you perform to distinguish hematite from copper? How would

you carry out this test?2. How could you distinguish copper from galena? What tool would you use?3. What would you do if two minerals had the same hardness and the same streak

color?

Properties of Minerals

Mineral Hardness Streak

Copper 2.5–3 copper-red

Galena 2.5 dark gray

Gold 2.5–3 yellow

Hematite 5.5–6.5 red to brown

Magnetite 6–6.5 black

Silver 2.5–3 silver-white

Fluorite

Graphite

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SECTION 2 Mineral Identification 71

Streak When a mineral is rubbed across a piece ofunglazed porcelain tile, as in Figure 9, a streak of pow-dered mineral is left behind. Streak is the color of a min-eral when it is in a powdered form. The streak test worksonly for minerals that are softer than the streak plate.Gold and pyrite can be distinguished by a streak test.Gold has a yellow streak and pyrite has a greenish-blackor brownish-black streak.

Some soft minerals will leave a streak even on paper.The last time you used a pencil to write on paper, you lefta streak of the mineral graphite. One reason that graphiteis used in pencil lead is because it is soft enough to leavea streak on paper.

Why do gold and pyrite leave a streak,but quartz does not?

Cleavage and Fracture The way a mineral breaks is anotherclue to its identity. Minerals that break along smooth, flat sur-faces have cleavage (KLEE vihj). Cleavage, like hardness, is deter-mined partly by the arrangement of the mineral’s atoms. Mica isa mineral that has one perfect cleavage. Figure 10 shows howmica breaks along smooth, flat planes. If you were to take a layercake and separate its layers, you would show that the cake hascleavage. Not all minerals have cleavage. Minerals that break withuneven, rough, or jagged surfaces have fracture. Quartz is a min-eral with fracture. If you were to grab a chunk out of the side ofthat cake, it would be like breaking a mineral that has fracture.

Figure 9 Streak is more usefulfor mineral identification than ismineral color. Hematite, for exam-ple, can be dark red, gray, or silverin color. However, its streak isalways dark reddish-brown.

Figure 10 Weak or fewer bondswithin the structures of mica andhalite allow them to be brokenalong smooth, flat cleavage planes. Infer If you broke quartz, would itlook the same?

Halite

Mica

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Self Check1. Compare and contrast a mineral fragment that has one

cleavage direction with one that has only fracture.

2. Explain how an unglazed porcelain tile can be used toidentify a mineral.

3. Explain why streak often is more useful for mineralidentification than color.

4. Determine What hardness does a mineral have if itdoes not scratch glass but it scratches an iron nail?

5. Think Critically What does the presence of cleavageplanes within a mineral tell you about the chemicalbonds that hold the mineral together?

SummaryPhysical Properties

• Minerals are identified by observing theirphysical properties.

• Hardness is a measure of how easily a mineralcan be scratched.

• Luster describes how a mineral reflects light.• Specific gravity is the ratio of the weight of a

mineral sample compared to the weight of anequal volume of water.

• Streak is the color of a powdered mineral.• Minerals with cleavage break along smooth,

flat surfaces in one or more directions.

• Fracture describes any uneven manner inwhich a mineral breaks.

• Some minerals react readily with acid, form adouble image, or are magnetic.

6. Draw Conclusions A large piece of the mineral haliteis broken repeatedly into several perfect cubes. How can this be explained?

Other Properties Some minerals have unique properties.Magnetite, as you can guess by its name, is attracted to magnets.Lodestone, a form of magnetite, will pick up iron filings like amagnet, as shown in Figure 11. Light forms two separate rayswhen it passes through calcite, causing you to see a double imagewhen viewed through transparent specimens. Calcite also can beidentified because it fizzes when hydrochloric acid is put on it.

Now you know that you sometimes need more informationthan color and appearance to identify a mineral. You also mightneed to test its streak, hardness, luster, and cleavage or fracture.Although the overall appearance of a mineral can be differentfrom sample to sample, its physical properties remain the same.

Observing MineralPropertiesProcedure1. Obtain samples of some

of the following clear min-erals: gypsum, muscovitemica, halite, and calcite.

2. Place each sample over theprint on this page andobserve the letters.

Analysis1. Which mineral can be

identified by observing theprint’s double image?

2. What other special prop-erty is used to identify thismineral?

Figure 11 Some minerals arenatural magnets, such as thislodestone, which is a variety ofmagnetite.

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SECTION 3 Uses of Minerals 73

GemsWalking past the window of a jewelry store, you notice a

large selection of beautiful jewelry—a watch sparkling with dia-monds, a necklace holding a brilliant red ruby, and a gold ring.For thousands of years, people have worn and prized mineralsin their jewelry. What makes some minerals special? Whatunusual properties do they have that make them so valuable?

Properties of Gems As you can see in Figure 12, gems orgemstones are highly prized minerals because they are rare andbeautiful. Most gems are special varieties of a particular min-eral. They are clearer, brighter, or more colorful than commonsamples of that mineral. The difference between a gem and thecommon form of the same mineral can be slight. Amethyst is agem form of quartz that contains just traces of iron in its struc-ture. This small amount of iron gives amethyst a desirable pur-ple color. Sometimes a gem has a crystal structure that allows itto be cut and polished to a higher quality than that of a non-gem mineral. Table 2 lists popular gems and some locationswhere they have been collected.

Uses of Minerals

■ Describe characteristics of gemsthat make them more valuablethan other minerals.

■ Identify useful elements that arecontained in minerals.

Minerals are necessary materials fordecorative items and many manu-factured products.

Review Vocabularymetal: element that typically is ashiny, malleable solid that con-ducts heat and electricity well

New Vocabulary

• gem • ore

Figure 12 It is easy to see whygems are prized for their beautyand rarity. Shown here is TheImperial State Crown, made forQueen Victoria of England in 1838.It contains thousands of jewels,including diamonds, rubies,sapphires, and emeralds.

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Table 2 Minerals and Their Gems

Fun Facts Mineral Gem ExampleSome Important

Locations

Beryl is named for Beryl Emerald Colombia, Brazil,the element beryllium, South Africa,which it contains. North CarolinaSome crystals reachseveral meters in length.

A red spinel in the Spinel Ruby spinel Sri Lanka, Thailand,British crown jewels Myanmar (Burma)has a mass of 352carats. A carat is 0.2 g.

Purplish-blue examples Zoisite Tanzanite Tanzaniaof zoisite werediscovered in 1967near Arusha, Tanzania.

The most valuable Topaz (uncut) Topaz (gem) Siberia, Germany,examples are yellow, Japan, Mexico, Brazil,pink, and blue varieties. Colorado, Utah, Texas,

California, Maine,Virginia, South Carolina

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Fun Facts Mineral Gem ExampleSome Important

Locations

Olivine composes Olivine Peridot Myanmar (Burma),a large part of Zebirget (Saint John’sEarth’s upper mantle. Island, located in theIt is also present Red Sea), Arizona,in moon rocks. New Mexico

Garnet is a common Garnet Almandine Ural Mountains,mineral found in Italy, Madagascar,a wide variety of rock Czech Republic, India,types. The red color of Sri Lanka, Brazil,the variety almandine North Carolina, Arizona,is caused by iron in New Mexicoits crystal structure.

Quartz makes up Quartz Amethyst Colorless varieties inabout 30 percent Hot Springs, Arkansas;of Earth’s Amethyst in Brazil,continental crust. Uruguay, Madagascar,

Montana, NorthCarolina, California,Maine

The blue color of Corundum Blue sapphire Thailand, Cambodia,sapphire is caused Sri Lanka, Kashmirby iron or titaniumin corundum. Chromiumin corundum producesthe red color of ruby.

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Important Gems All gems are prized, but some are trulyspectacular and have played an important role in history. Forexample, the Cullinan diamond, found in South Africa in 1905,was the largest uncut diamond ever discovered. Its mass was3,106.75 carats (about 621 g). The Cullinan diamond was cutinto 9 main stones and 96 smaller ones. The largest of these iscalled the Cullinan 1 or Great Star of Africa. Its mass is530.20 carats (about 106 g), and it is now part of the Britishmonarchy’s crown jewels, shown in Figure 13A.

Another well-known diamond is the blue Hope diamond,shown in Figure 13B. This is perhaps the most notorious of alldiamonds. It was purchased by Henry Philip Hope around 1830,after whom it is named. Because his entire family as well as alater owner suffered misfortune, the Hope diamond has gaineda reputation for bringing its owner bad luck. The Hope dia-mond’s mass is 45.52 carats (about 9 g). Currently it is displayedin the Smithsonian Institution in Washington, D.C.

Useful Gems In addition to their beauty, some gems serveuseful purposes. You learned earlier that diamonds have a hard-ness of 10 on Mohs scale. They can scratch almost any material—a property that makes them useful as industrial abrasives andcutting tools. Other useful gems include rubies, which are used toproduce specific types of laser light. Quartz crystals are used inelectronics and as timepieces. When subjected to an electric field,quartz vibrates steadily, which helps control frequencies in elec-tronic devices and allows for accurate timekeeping.

Most industrial diamonds and other gems are synthetic,which means that humans make them. However, the study ofnatural gems led to their synthesis, allowing the synthetic vari-eties to be used by humans readily.

The Great Star of Africa is partof a sceptre in the collection ofBritish crown jewels.

Beginning in 1668, the Hope diamond was part of theFrench crown jewels. Then known as the French Blue, it wasstolen in 1792 and later surfaced in London, England in 1812.

Topic: Gemstone Data Visit for Weblinks to information about gems atthe Smithsonian Museum ofNatural History.

Activity List three importantexamples of gems other than thosedescribed on this page. Prepare adata table with the heads GemName/Type, Weight (carats/grams),Mineral, and Location. Fill in thetable entries for the gemstonesyou selected.

earth.msscience.com

Figure 13 These gems areamong the most famous examplesof precious stones.

(l)Francis G. Mayer/CORBIS, (r)Smithsonian Institution

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Useful Elements in MineralsGemstones are perhaps the best-known use of minerals, but

they are not the most important. Look around your home. Howmany things made from minerals can you name? Can you findanything made from iron?

Ores Iron, used in everything from frying pans to ships, isobtained from its ore, hematite. A mineral or rock is an ore if itcontains a useful substance that can be mined at a profit.Magnetite is another mineral that contains iron.

When is a mineral also an ore?

Aluminum sometimes is refined, or puri-fied, from the ore bauxite, shown in

Figure 14. In the process of refining aluminum, aluminum oxidepowder is separated from unwanted materials that are present inthe original bauxite. After this, the aluminum oxide powder isconverted to molten aluminum by a process called smelting.

During smelting, a substance is melted to separate it fromany unwanted materials that may remain. Aluminum can bemade into useful products like bicycles, soft-drink cans, foil, andlightweight parts for airplanes and cars. The plane flown by theWright brothers during the first flight at Kitty Hawk had anengine made partly of aluminum.

Figure 14 Bauxite, an ore of aluminum,is processed to make pure aluminum metalfor useful products.

Bauxite

Historical Mineralogy Anearly scientific descriptionof minerals was publishedby Georgius Agricola in1556. Use print and onlineresources to research themining techniques dis-cussed by Agricola in hiswork De Re Metallica.

(l)Fred Whitehead/Earth Scenes, (inset)Doug Martin

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Vein Minerals Under certain conditions, metallic elementscan dissolve in fluids. These fluids then travel through weak-nesses in rocks and form mineral deposits. Weaknesses in rocksinclude natural fractures or cracks, faults, and surfaces betweenlayered rock formations. Mineral deposits left behind that fill inthe open spaces created by the weaknesses are called vein min-eral deposits.

How do fluids move through rocks?

Sometimes vein mineral deposits fill in the empty spacesafter rocks collapse. An example of a mineral that can form inthis way is shown in Figure 15. This is the shiny mineral spha-lerite, a source of the element zinc, which is used in batteries.Sphalerite sometimes fills spaces in collapsed limestone.

Minerals Containing Titanium You might own golf clubswith titanium shafts or a racing bicycle containing titanium.Perhaps you know someone who has a titanium hip or kneereplacement. Titanium is a durable, lightweight, metallic ele-ment derived from minerals that contain this metal in theircrystal structures. Two minerals that are sources of the element

titanium are ilmenite (IHL muh nite)and rutile (rew TEEL), shown inFigure 16. Ilmenite and rutile arecommon in rocks that form whenmagma cools and solidifies. Theyalso occur as vein mineral depositsand in beach sands.

Figure 16 Rutile and ilmeniteare common ore minerals of theelement titanium.

Rutile Ilmenite

Figure 15 The mineral sphalerite(greenish when nearly pure) is animportant source of zinc. Iron oftenis coated with zinc to prevent rust ina process called galvanization.

(t)Matt Meadows, (bl)Paul Silverman/Fundamental Photographs, (br)Biophoto Associates/Photo Researchers

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Self Check1. Explain why the Cullinan diamond is an important gem.

2. Identify Examine Table 2. What do rubies and sapphireshave in common?

3. Describe how vein minerals form.

4. Explain why bauxite is considered to be a useful rock.

5. Think Critically Titanium is nontoxic. Why is thisimportant in the manufacture of artificial body parts?

SummaryGems

• Gems are highly prized mineral specimensoften used as decorative pieces in jewelry orother items.

• Some gems, especially synthetic ones, haveindustrial uses.

Useful Elements in Minerals

• Economically important quantities of usefulelements or compounds are present in ores.

• Ores generally must be processed to extractthe desired material.

• Iron, aluminum, zinc, and titanium are com-mon metals that are extracted from minerals.

6. Use Percentages Earth’s average continental crustcontains 5 percent iron and 0.007 percent zinc. Howmany times more iron than zinc is present in average continental crust?

Uses for Titanium Titanium is used in automobile bodyparts, such as connecting rods, valves, and suspension springs.Low density and durability make it useful in the manufacture ofaircraft, eyeglass frames, and sports equipment such as tennisrackets and bicycles. Wheelchairs used by people who want torace or play basketball often are made from titanium, as shownin Figure 17. Titanium is one of many examples of useful mate-rials that come from minerals and that enrich humans’ lives.

Figure 17 Wheelchairs used forracing and playing basketball oftenhave parts made from titanium.

earth.msscience.com/self_check_quizJim Cummins/Getty Images

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Real-World QuestionAlthough certain minerals can be identified by observing only oneproperty, others require testing several properties to identify them.How can you identify unknown minerals?

Procedure1. Copy the data table into your Science Journal. Obtain a set of

unknown minerals.

2. Observe a numbered mineral specimen carefully. Write a star inthe table entry that represents what you hypothesize is an impor-tant physical property. Choose one or two properties that you thinkwill help most in identifying the sample.

3. Perform tests to observe your chosen properties first.a. To estimate hardness:

■ Rub the sample firmly against objects of known hardnessand observe whether it leaves a scratch on the objects.

■ Estimate a hardness range based on which items the mineralscratches.

b. To estimate specific gravity: Perform a density measurement.■ Use the pan balance to determine the sample’s mass, in

grams.

Goals■ Hypothesize which

properties of each min-eral are most useful foridentification purposes.

■ Test your hypothesis asyou attempt to identifyunknown mineralsamples.

Materialsmineral samplesmagnifying lenspan balancegraduated cylinderwaterpiece of copper *copper pennyglass platesmall iron nailsteel filestreak plate5% HCI with dropperMohs scale of hardness Minerals Appendix*minerals field guidesafety goggles*Alternate materials

Safety Precautions

WARNING: If an HCl spilloccurs, notify your teacherand rinse with cool wateruntil you are told to stop.Do not taste, eat, or drinkany lab materials.


80 CHAPTER 3 MineralsMatt Meadows

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■ Measure its volume using a graduated cylinder partially filledwith water. The amount of water displaced by the immersedsample, in mL, is an estimate of its volume in cm3.

■ Divide mass by volume to determine density. This number,without units, is comparable to specific gravity.

4. With the help of the Mineral Appendix or a field guide, attemptto identify the sample using the properties from step 2. Performmore physical property observations until you can identify thesample. Repeat steps 2 through 4 for each unknown.

Analyze Your Data1. Which properties were most useful in identifying your samples? Which proper-

ties were least useful?

2. Compare the properties that worked best for you with those that worked bestfor other students.

Conclude and Apply1. Determine two properties that distinguish clear, transparent quartz from clear,

transparent calcite. Explain your choice of properties.

2. Which physical properties would be easiest to determine if you found a mineralspecimen in the field?

LAB 81

For three minerals, list physical propertiesthat were important for their identification.For more help, refer to the Science SkillHandbook.

Physical Properties of Minerals

Sample

Hardness

Cleavage Color

Specific

Luster Crystal Other Mineral

Number

or Gravity

and Shape Properties Name

Fracture Streak

1

2

etc.

(t)Doug Martin, (inset)José Manuel Sanchis Calvete/CORBIS, (bl)Andrew J. Martinez/Photo Researchers, (br)Charles D. Winter/Photo Researchers

Do not write in this book.

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Trailblazing scientist and humanitarian

SCIENCEANDHISTORY

SCIENCE CAN CHANGE THE COURSE OF HISTORY!

Dr. DorothyCrowfoot Hodgkin

Dr. DorothyCrowfoot Hodgkin

What contributions did Dorothy CrowfootHodgkin make to science?

Dr. Hodgkin used a method called X-ray crys-tallography (kris tuh LAH gruh fee) to figure outthe structures of crystalline substances, includingvitamin B12, vitamin D, penicillin, and insulin.

What’s X-ray crystallography?Scientists expose a crystalline sample to

X rays. As X rays travel through a crystal, the crys-tal diffracts, or scatters, the

X rays into a regular pat-tern. Like an individ-

ual’s fingerprints,each crystalline sub-stance has a unique

diffraction pattern.Crystallography

has applica-tions in thelife, Earth,and physical

sciences. For example, geologists use X-raycrystallography to identify and study mineralsfound in rocks.

What were some obstacles Hodgkinovercame?

During the 1930s, there were few womenscientists. Hodgkin was not even allowed toattend meetings of the chemistry faculty whereshe taught because she was a woman. Eventually,she won over her colleagues with her intelli-gence and tenacity.

How does Hodgkin’s research help peopletoday?

Dr. Hodgkin’s discovery of the structure ofinsulin helped scientists learn how to controldiabetes, a disease that affects more than 15 mil-lion Americans. Diabetics’ bodies are unable toprocess sugar efficiently. Diabetes can be fatal.Fortunately, Dr. Hodgkin’s research with insulinhas saved many lives.

Like X rays, electrons arediffracted by crystalline

substances, revealinginformation about theirinternal structures and

symmetry. This electrondiffraction pattern of

titanium was obtained withan electron beam focused

along a specific direction inthe crystal.

Research Look in reference books or go to the Glencoe ScienceWeb site for information on how X-ray crystallography is used tostudy minerals. Write your findings and share them with your class. For more information, visit

earth.msscience.com/time

1910–1994

(bkgd)Science Photo Library/Custom Medical Stock Photo, (bl)Bettmann/CORBIS

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Copy and complete the following concept map about minerals. Use the following words and phrases:the way a mineral breaks, the way a mineral reflects light, ore, a rare and beautiful mineral, howeasily a mineral is scratched, streak, and a useful substance mined for profit.

Minerals

1. Much of what you use each day is made atleast in some part from minerals.

2. All minerals are formed by naturalprocesses and are inorganic solids withdefinite chemical compositions and orderlyarrangements of atoms.

3. Minerals have crystal structures in one ofsix major crystal systems.


1. Hardness is a measure of how easily a min-eral can be scratched.

2. Luster describes how light reflects from amineral’s surface.

3. Streak is the color of the powder left by amineral on an unglazed porcelain tile.

4. Minerals that break along smooth, flat sur-faces have cleavage. When minerals breakwith rough or jagged surfaces, they are dis-playing fracture.

5. Some minerals have special properties thataid in identifying them. For example, mag-netite is identified by its attraction to amagnet.

Uses of Minerals

1. Gems are minerals that are more rare andbeautiful than common minerals.

2. Minerals are useful for their physical prop-erties and for the elements they contain.

CHAPTER STUDY GUIDE 83

whichmeans

whichmeans

some properties of some uses

whichmeans

whichmeans

whichis

whichis

Minerals

Color of amineral in powdered

form

GemCleavage and fracture

LusterHardness

earth.msscience.com/interactive_tutor

José Manuel Sanchis Calvete/CORBIS

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Explain the difference between the vocabularywords in each of the following sets.

1. cleavage—fracture

2. crystal—mineral

3. luster—streak

4. magma—crystal

5. hardness—specific gravity

6. ore—mineral

7. crystal—luster

8. mineral—silicate

9. gem—crystal

10. streak—specific gravity

Choose the word or phrase that best answers thequestion.

11. Which is a characteristic of a mineral?A) It can be a liquid.B) It is organic.C) It has no crystal structure.D) It is inorganic.

12. What must all silicates contain?A) magnesiumB) silicon and oxygenC) silicon and aluminumD) oxygen and carbon

13. What is the measure of how easily a min-eral can be scratched?A) lusterB) hardnessC) cleavageD) fracture

Use the photo below to answer question 14.

14. Examine the photo of quartz above. Inwhat way does quartz break?A) cleavage C) lusterB) fracture D) flat planes

15. Which of the following must crystallinesolids have?A) carbonatesB) cubic structuresC) orderly arrangement of atomsD) cleavage

16. What is the color of a powdered mineralformed when rubbing it against anunglazed porcelain tile?A) lusterB) densityC) hardnessD) streak

17. Which is hardest on Mohs scale?A) talcB) quartzC) diamondD) feldspar

84 CHAPTER REVIEW

cleavage p. 71crystal p. 63fracture p. 71gem p. 73hardness p. 69luster p. 70

magma p. 65mineral p. 62ore p. 77silicate p. 66specific gravity p. 70streak p. 71

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18. Classify Water is an inorganic substancethat is formed by natural processes onEarth. It has a unique composition.Sometimes water is a mineral and othertimes it is not. Explain.

19. Determine how many sides a perfect saltcrystal has.

20. Apply Suppose you let a sugar solutionevaporate, leaving sugar crystals behind.Are these crystals minerals? Explain.

21. Predict Will a diamond leave a streak on astreak plate? Explain.

22. Collect Data Make an outline of how at leastseven physical properties can be used toidentify unknown minerals.

23. Explain how you would use Table 1 to deter-mine the hardness of any mineral.

24. Concept Map Copy and complete the con-cept map below, which includes two crys-tal systems and two examples from eachsystem. Use the following words andphrases: hexagonal, corundum, halite,fluorite, and quartz.

25. Display Make a display that shows the sixcrystal systems of minerals. Research thecrystal systems of minerals and give threeexamples for each crystal system. Indicatewhether any of the minerals are found inyour state. Describe any important usesof these minerals. Present your display tothe class.

CHAPTER REVIEW 85

26. Mineral Volume Recall that 1 mL � 1 cm3.Suppose that the volume of water in a gradu-ated cylinder is 107.5 mL. A specimen ofquartz, tied to a piece of string, is immersed inthe water. The new water level reads 186 mL.What is the volume, in cm3, of the piece ofquartz?

Use the graph below to answer questions 27 and 28.

27. Zinc Use According to the graph above, whatwas the main use of zinc consumed in theUnited States between 1978 and 1998?

28. Metal Products According to the graph, approx-imately how many thousand metric tons of zincwere used to make brass and bronze productsin 1998?

Cubic

U.S. Slab Zinc Consumption 1978–1998

Con

sum

pti

on(t

hou

san

ds

of m

etri

c to

ns)

pp

0

200

400

600

800

1,000

1,200

1,400

1978 1983 1988 1993 1998Year

Galvanizing to prevent corrosionBrass and bronze productsZinc-based alloysOther uses

earth.msscience.com/chapter_review

CrystalSystems

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Record your answers on the answer sheetprovided by your teacher or on a sheet of paper.


1. To which crystal system does the crystalshown above belong? A. hexagonal C. triclinicB. cubic D. monoclinic

2. Which of the following is a common rock-forming mineral?A. azurite C. quartzB. gold D. diamond

3. Which term refers to the resistance of amineral to scratching?A. hardness C. lusterB. specific gravity D. fracture

4. Which is a special property of the mineralmagnetite?A. attracted by a magnetB. fizzes with dilute hydrochloric acidC. forms a double imageD. has a salty taste

5. Which causes some minerals to break alongsmooth, flat surfaces?A. streak C. lusterB. cleavage D. fracture

6. Which of these forms in cracks or alongfaults?A. bauxiteB. silicatesC. vein mineralsD. rock-forming minerals

7. Which is the most abundant element inEarth’s crust?A. silicon C. ironB. manganese D. oxygen

Use the table below to answer questions 8–10.

8. Which mineral in the table is softest?A. diamond C. talcB. feldspar D. gypsum

9. Which mineral will scratch feldspar butnot topaz?A. quartz C. apatiteB. calcite D. diamond

10. After whom is the scale shown abovenamed?A. Neil ArmstrongB. Friedrich MohsC. Alfred WegenerD. Isaac Newton

86 STANDARDIZED TEST PRACTICE

If you are taking a timed test, keep track of time during thetest. If you find that you’re spending too much time on amultiple-choice question, mark your best guess and move on.

Mineral Hardness

Talc 1

Gypsum 2

Calcite 3

Fluorite 4

Apatite 5

Feldspar 6

Quartz 7

Topaz 8

Corundum 9

Diamond 10

José Manuel Sanchis Calvete/CORBIS

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STANDARDIZED TEST PRACTICE 87

Record your answers on the answer sheetprovided by your teacher or on a sheet of paper.

11. What is the definition of a mineral?

12. Why are gems valuable?

13. Explain the difference between fractureand cleavage.

14. Why is mineral color sometimes not help-ful for identifying minerals?

Use the conversion factor and table below to answer

questions 15–17.

1.0 carat = 0.2 grams

15. How many grams is the Uncle Samdiamond?

16. How many carats is the Punch Jonesdiamond?

17. How many grams of diamond were pro-duced in western Australia in 2001?

18. What is the source of most of the diamondsthat are used for industrial purposes?

19. Explain how minerals are useful to society.Describe some of their uses.

Record your answers on a sheet of paper.


20. The mineral crystals in the rock aboveformed when magma cooled and are visi-ble with the unaided eye. Hypothesizeabout how fast the magma cooled.

21. What is a crystal system? Why is it usefulto classify mineral crystals this way?

22. How can a mineral be identified using itsphysical properties?

23. What is a crystal? Do all crystals havesmooth crystal faces? Explain.

24. Are gases that are given off by volcanoesminerals? Why or why not?

25. What is the most abundant mineral groupin Earth’s crust? What elements always arefound in the minerals included in thisgroup?

26. Several layers are peeled from a piece ofmuscovite mica? What property of miner-als does this illustrate? Describe this prop-erty in mica.

Diamond Carats Grams

Uncle Sam: 40.4 ?largest diamond found in United States

Punch Jones: ? 6.89second largest U.S. diamond; named after boy who discovered it

Theresa: 21.5 4.3discovered in Wisconsin in 1888

2001 diamond 21,679,930 ?production from western Australia

earth.msscience.com/standardized_test

Breck P. Kent/Earth Scenes

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Glencoe Earth ScienceContents in BriefStudent Edition Table of ContentsUnit 1: Earth MaterialsChapter 1: The Nature of ScienceLaunch Lab: Measure in SIFoldablesSection 1: Science All AroundScience OnlineIntegrate Life ScienceMiniLAB: Designing an ExperimentVisualizing the History of Earth Science Technology

Section 2: Scientific EnterpriseScience OnlineMiniLAB: Observing a Scientific LawIntegrate CareerApplying Science: How can bias affect your observations?Lab: Understanding Science ArticlesLab: Testing Variables of a PendulumScience and Language Arts: "The Microscope"

Chapter 1 Study GuideChapter 1 ReviewChapter 1 Standardized Test Practice

Chapter 2: MatterLaunch Lab: Change the State of WaterFoldablesSection 1: AtomsMiniLAB: Searching for ElementsIntegrate Health

Section 2: Combinations of AtomsScience OnlineMiniLAB: Classifying Forms of MatterLab: Scales of Measurement

Section 3: Properties of MatterApplying Math: Calculating DensityScience OnlineVisualizing States of MatterLab: Determining DensityScience Stats: Amazing Atoms


Chapter 3: MineralsLaunch Lab: Distinguish Rocks from MineralsFoldablesSection 1: MineralsMiniLAB: Inferring Salt's Crystal SystemVisualizing Crystal SystemsIntegrate PhysicsLab: Crystal Formation

Section 2: Mineral IdentificationApplying Science: How can you identify minerals?MiniLAB: Observing Mineral Properties

Section 3: Uses of MineralsScience OnlineIntegrate Social StudiesLab: Mineral IdentificationScience and History: Dr. Dorothy Crowfoot Hodgkin


Chapter 4: RocksLaunch Lab: Observe and Describe RocksFoldablesSection 1: The Rock CycleMiniLAB: Modeling RockVisualizing the Rock Cycle

Section 2: Igneous RocksScience OnlineIntegrate ChemistryLab: Igneous Rock Clues

Section 3: Metamorphic RocksScience Online

Section 4: Sedimentary RocksMiniLAB: Classifying SedimentsIntegrate CareerApplying Math: Coal FormationLab: Sedimentary RocksScience and Society: Australia's Controversial Rock Star


Chapter 5: Earth's Energy and Mineral ResourcesLaunch Lab: Finding Energy ReservesFoldablesSection 1: Nonrenewable Energy ResourcesIntegrate Life Science Science OnlineVisualizing Methane HydratesMiniLAB: Practicing Energy Conservation

Section 2: Renewable Energy ResourcesIntegrate CareerScience OnlineLab: Soaking Up Solar Energy

Section 3: Mineral ResourcesMiniLAB: Observing the Effects of InsulationApplying Science: Why should you recycle?Lab: Home Sweet HomeOops! Accidents in Science: Black Gold!


Unit 2: The Changing Surface of the EarthChapter 6: Views of EarthLaunch Lab: Describe LandformsFoldablesSection 1: LandformsMiniLAB: Profiling the United StatesIntegrate PhysicsScience Online

Section 2: ViewpointsMiniLAB: Interpreting Latitude and LongitudeIntegrate Social Studies

Section 3: MapsIntegrate PhysicsVisualizing Topographic MapsScience OnlineApplying Science: How can you create a cross section from a geologic map?Lab: Making a Topographic MapLab: Constructing LandformsScience and History: Location, Location


Chapter 7: Weathering and SoilLaunch Lab: Stalactites and StalagmitesFoldablesSection 1: WeatheringScience OnlineMiniLAB: Observing the Formation of Rust

Section 2: The Nature of SoilVisualizing Soil FormationMiniLAB: Comparing Components of SoilIntegrate ChemistryApplying Math: Soil TextureLab: Soil Texture

Section 3: Soil ErosionIntegrate CareerScience OnlineLab: Weathering ChalkScience and Language Arts: Landscape, History, and the Pueblo Imagination


Chapter 8: Erosional ForcesLaunch Lab: Demonstrate Sediment MovementFoldablesSection 1: Erosion by GravityMiniLAB: Modeling SlumpIntegrate Physics

Section 2: GlaciersScience OnlineLab: Glacial Grooving

Section 3: WindIntegrate HistoryApplying Science: What factors affect wind erosion?MiniLAB: Observing How Soil Is Held in PlaceScience OnlineVisualizing How Dunes Form and MigrateLab: Blowing in the WindScience Stats: Losing Against Erosion


Chapter 9: Water Erosion and DepositionLaunch Lab: Model How Erosion WorksFoldablesSection 1: Surface WaterIntegrate CareerScience OnlineVisualizing Stream DevelopmentScience OnlineMiniLAB: Observing Runoff Collection

Section 2: GroundwaterMiniLAB: Measuring Pore SpaceApplying Math: Groundwater FlowIntegrate Chemistry

Section 3: Ocean ShorelineLab: Classifying Types of SandLab: Water Speed and ErosionScience and Society: Sands in Time


Unit 3: Earth's Internal ProcessesChapter 10: Plate TectonicsLaunch Lab: Reassemble an ImageFoldablesSection 1: Continental DriftScience OnlineMiniLAB: Interpreting Fossil Data

Section 2: Seafloor SpreadingIntegrate ChemistryLab: Seafloor Spreading Rates

Section 3: Theory of Plate TectonicsScience OnlineApplying Science: How well do the continents fit together?Visualizing Plate BoundariesMiniLAB: Modeling Convection CurrentsIntegrate CareerIntegrate PhysicsLab: Predicting Tectonic ActivityScience and Language Arts: Listening In


Chapter 11: EarthquakesLaunch Lab: Why do earthquakes occur?FoldablesSection 1: Forces Inside EarthSection 2: Features of EarthquakesIntegrate PhysicsVisualizing Seismic WavesScience OnlineMiniLAB: Interpreting Seismic Wave DataLab: Epicenter Location

Section 3: People and EarthquakesIntegrate CareerScience OnlineApplying Math: Earthquake EnergyMiniLAB: Modeling Seismic-Safe StructuresLab: Earthquake DepthsScience Stats: Moving Earth!


Chapter 12: VolcanoesLaunch Labs: Map a VolcanoFoldablesSection 1: Volcanoes and Earth's Moving PlatesIntegrate CareerMiniLAB: Modeling Magma Movement

Section 2: Types of VolcanoesScience OnlineVisualizing LavaIntegrate HealthMiniLAB: Modeling Volcanic ConesLab: Identifying Types of Volcanoes

Section 3: Igneous Rock FeaturesApplying Math: Classifying Igneous RocksScience OnlineLab: How do calderas form?Oops! Accidents in Science: Buried in Ash


Unit 4: Change and Earth's HistoryChapter 13: Clues to Earth's PastLaunch Lab: Clues to Life's PastFoldablesSection 1: FossilsMiniLAB: Predicting Fossil PreservationIntegrate Social StudiesIntegrate Life Science

Section 2: Relative Ages of RocksScience OnlineVisualizing UnconformitiesScience OnlineLab: Relative Ages

Section 3: Absolute Ages of RocksMiniLAB: Modeling Carbon-14 DatingScience OnlineApplying Science: When did the Iceman die?Lab: Trace FossilsOops! Accidents in Science: The World's Oldest Fish Story


Chapter 14: Geologic TimeLaunch Lab: Survival Through TimeFoldablesSection 1: Life and Geologic TimeSection 2: Early Earth HistoryIntegrate ChemistryMiniLAB: Dating Rock Layers with FossilsVisualizing Unusual Life-FormsScience OnlineLab: Changing Species

Section 3: Middle and Recent Earth HistoryScience OnlineApplying Math: Calculating Extinction By Using PercentagesMiniLAB: Calculating the Age of the Atlantic OceanLab: Discovering the PastScience Stats: Extinct!


Unit 5: Earth's Air and WaterChapter 15: AtmosphereLaunch Lab: Observe Air PressureFoldablesSection 1: Earth's AtmosphereScience OnlineApplying Science: How does altitude affect air pressure?MiniLAB: Determining if Air Has MassIntegrate Life ScienceLab: Evaluating Sunscreens

Section 2: Energy Transfer in the AtmosphereIntegrate PhysicsMiniLAB: Modeling Heat Transfer

Section 3: Air MovementScience OnlineVisualizing Global WindsLab: The Heat Is OnScience and Language Arts: Song of the Sky Loom


Chapter 16: WeatherLaunch Lab: What causes rain?FoldablesSection 1: What is weather?Integrate Life Science MiniLAB: Determining Dew PointApplying Math: Dew Point

Section 2: Weather PatternsScience OnlineScience OnlineVisualizing TornadoesIntegrate Environment

Section 3: Weather ForecastsMiniLAB: Measuring RainLab: Reading a Weather MapLab: Measuring Wind SpeedScience and Society: Rainmakers


Chapter 17: ClimateLaunch Lab: Tracking World ClimatesFoldablesSection 1: What is climate?MiniLAB: Observing Solar RadiationIntegrate PhysicsApplying Science: How do cities influence temperature?

Section 2: Climate TypesSection 3: Climatic ChangesMiniLAB: Modeling El NiñoVisualizing El Niño and La NiñaIntegrate CareerScience OnlineScience OnlineLab: The Greenhouse EffectLab: MicroclimatesScience and History: The Year There Was No Summer


Chapter 18: Ocean MotionLaunch Lab: Explore How Currents WorkFoldablesSection 1: Ocean WaterSection 2: Ocean CurrentsScience OnlineMiniLAB: Modeling a Density CurrentIntegrate CareerApplying Math: Density of Salt Water

Section 3: Ocean Waves and TidesMiniLAB: Modeling Water Particle MovementVisualizing Wave MovementScience OnlineIntegrate Life ScienceLab: Wave PropertiesLab: Sink or Float?Science and Language Arts: "The Jungle of Ceylon"


Chapter 19: OceanographyLaunch Lab: How deep is the ocean?FoldablesSection 1: The SeafloorScience OnlineApplying Math: Calculating a Feature's SlopeMiniLAB: Modeling the Mid-Atlantic RidgeLab: Mapping the Ocean Floor

Section 2: Life in the OceanIntegrate CareerIntegrate ChemistryMiniLAB: Observing PlanktonScience OnlineVisualizing the Rocky Shore Habitat

Section 3: Ocean PollutionLab: Resources from the OceansOops! Accidents in Science: Strange Creatures from the Ocean Floor


Unit 6: You and the EnvironmentChapter 20: Our Impact on LandLaunch Lab: What happens as the human population grows?FoldablesSection 1: Population Impact on the EnvironmentScience OnlineIntegrate Career

Section 2: Using LandMiniLAB: Modeling Earth's FarmlandApplying Science: How does land use affect stream discharge?Integrate PhysicsLab: What to Wear?

Section 3: Conserving ResourcesMiniLAB: Classifying Your Trash for One DayVisualizing Trash DisposalLab: A World Full of PeopleScience and Society: Hazardous Waste


Chapter 21: Our Impact on Water and AirLaunch Lab: Is pollution always obvious?FoldablesSection 1: Water PollutionApplying Math: Surface Water PollutionVisualizing Sewage TreatmentIntegrate CareerIntegrate HealthScience OnlineLab: Elements in Water

Section 2: Air PollutionMiniLAB: Identifying Acid RainScience OnlineMiniLAB: Examining the Content of AirLab: What's in the air?Science and History: Meet Rachel Carson


Unit 7: AstronomyChapter 22: Exploring SpaceLaunch Lab: An Astronomer's ViewFoldablesSection 1: Radiation from SpaceIntegrate HealthMiniLAB: Observing Effects of Light PollutionLab: Building a Reflecting Telescope

Section 2: Early Space MissionsApplying Math: Drawing by NumbersIntegrate CareerVisualizing Space ProbesScience OnlineMiniLAB: Modeling a Satellite

Section 3: Current and Future Space MissionsScience OnlineScience OnlineLab: Star SightingsScience and Society: Cities in Space


Chapter 23: The Sun-Earth-Moon SystemLaunch Lab: Model Rotation and RevolutionFoldablesSection 1: EarthIntegrate Life Science MiniLAB: Making Your Own CompassScience OnlineScience Online

Section 2: The Moon—Earth's SatelliteMiniLAB: Comparing the Sun and the MoonScience OnlineIntegrate CareerVisualizing the Moon's SurfaceApplying Science: What will you use to survive on the Moon?Lab: Moon Phases and Eclipses

Section 3: Exploring Earth's MoonScience OnlineLab: Tilt and TemperatureScience and History: The Mayan Calendar


Chapter 24: The Solar SystemLaunch Lab: Model Crater FormationFoldablesSection 1: The Solar SystemScience OnlineIntegrate PhysicsVisualizing the Solar System's FormationLab: Planetary Orbits

Section 2: The Inner PlanetsMiniLAB: Inferring Effects of GravityScience OnlineApplying Math: Diameter of Mars

Section 3: The Outer PlanetsMiniLAB: Modeling PlanetsIntegrate Language Arts

Section 4: Other Objects in the Solar SystemLab: Solar System Distance ModelOops! Accidents in Science: It Came from Outer Space!


Chapter 25: Stars and GalaxiesLaunch Lab: Why do clusters of galaxies move apart?FoldablesSection 1: StarsMiniLAB: Observing Star PatternsApplying Science: Are distance and brightness related?

Section 2: The SunScience OnlineLab: Sunspots

Section 3: Evolution of StarsScience OnlineIntegrate ChemistryIntegrate History

Section 4: Galaxies and the UniverseMiniLAB: Measuring Distance in SpaceVisualizing the Big Bang TheoryLab: Measuring ParallaxScience Stats: Stars and Galaxies


Student ResourcesScience Skill HandbookScientific MethodsSafety SymbolsSafety in the Science Laboratory

Extra Try at Home LabsTechnology Skill HandbookComputer SkillsPresentation Skills

Math Skill HandbookMath ReviewScience Applications

Reference HandbooksWeather Map SymbolsRocks MineralsPeriodic Table of the ElementsTopographic Map Symbols

English/Spanish GlossaryIndexCredits

Feature ContentsCross-Curricular ReadingsNational GeographicUnit OpenersVisualizing

TIME Science and SocietyTIME Science and HistoryOops! Accidents in ScienceScience and Language ArtsScience Stats

LABSLaunch LABMiniLABMiniLAB Try at HomeOne-Page LabsTwo-Page LabsDesign Your Own LabsModel and Invent LabsUse the Internet Labs

ActivitiesApplying MathApplying ScienceIntegrateScience OnlineStandardized Test Practice

Student WorksheetsChapter 1: The Nature of ScienceChapter 2: MatterChapter 3: MineralsChapter 4: RocksChapter 5: Earth's Energy and Mineral ResourcesChapter 6: Views of EarthChapter 7: Weathering and SoilChapter 8: Erosional ForcesChapter 9: Water Erosion and DepositionChapter 10: Plate TectonicsChapter 11: EarthquakesChapter 12: VolcanoesChapter 13: Clues to Earth's PastChapter 14: Geologic TimeChapter 15: AtmosphereChapter 16: WeatherChapter 17: ClimateChapter 18: Ocean MotionChapter 19: OceanographyChapter 20: Our Impact on LandChapter 21: Our Impact on Water and AirChapter 22: Exploring SpaceChapter 23: The Sun-Earth-Moon SystemChapter 24: The Solar SystemChapter 25: Stars and GalaxiesProbeware LabsTo the StudentGetting Started with ProbewareSafety in the LabSafety SymbolsLife Science LabsLab 1: Size Limits of CellsLab 2: Exercise and Heart RateLab 3: Cooking with BacteriaLab 4: Sweat is CoolLab 5: Biodiversity and Ecosystems

Earth Science LabsLab 6: The Effect of Acid Rain on LimestoneLab 7: The Formation of CavesLab 8: Measuring EarthquakesLab 9: Predicting the WeatherLab 10: How are distance and light intensity related?

Physical Science LabsLab 11: How fast do you walk?Lab 12: Transforming EnergyLab 13: Endothermic and Exothermic ProcessesLab 14: Thermal ConductivityLab 15: Let the Races Begin!

Appendix A: Using the TI-73 to Create a HistogramAppendix B: Using the TI-83 Plus Graphing Calculator to Create a HistogramAppendix C: Using the TI-73 Graphing Calculator to Create a Box Plot and Display StatisticsAppendix D: Using the TI-83 Plus Graphing Calculator to Box Plot and Display StatisticsAppendix E: Using the TI-73 Graphing Calculator to Create a Circle Graph

Reading EssentialsChapter 1: The Nature of ScienceChapter 2: MatterChapter 3: MineralsChapter 4: RocksChapter 5: Earth's Energy and Mineral ResourcesChapter 6: Views of EarthChapter 7: Weathering and SoilChapter 8: Erosional ForcesChapter 9: Water Erosion and DepositionChapter 10: Plate TectonicsChapter 11: EarthquakesChapter 12: VolcanoesChapter 13: Clues to Earth's PastChapter 14: Geologic TimeChapter 15: AtmosphereChapter 16: WeatherChapter 17: ClimateChapter 18: Ocean MotionChapter 19: OceanographyChapter 20: Our Impact on LandChapter 21: Our Impact on Water and AirChapter 22: Exploring SpaceChapter 23: The Sun-Earth-Moon SystemChapter 24: The Solar SystemChapter 25: Stars and Galaxies

Mastering Standardized Tests - Student EditionChapter 1: The Nature of ScienceChapter 2: MatterChapter 3: MineralsChapter 4: RocksChapter 5: Earth's Energy and Mineral ResourcesChapter 6: Views of EarthChapter 7: Weathering and SoilChapter 8: Erosional ForcesChapter 9: Water Erosion and DepositionChapter 10: Plate TectonicsChapter 11: EarthquakesChapter 12: VolcanoesChapter 13: Clues to Earth's PastChapter 14: Geologic TimeChapter 15: AtmosphereChapter 16: WeatherChapter 17: ClimateChapter 18: Ocean MotionChapter 19: OceanographyChapter 20: Our Impact on LandChapter 21: Our Impact on Water and AirChapter 22: Exploring SpaceChapter 23: The Sun-Earth-Moon SystemChapter 24: The Solar SystemChapter 25: Stars and Galaxies

Science Inquiry LabsSafety SymbolsSafety GuidelinesSI Reference SheetLaboratory EquipmentScience as InquiryActivity 1: It's a Small WorldActivity 2: Designing a Classification SystemActivity 3: Effects of Acid RainActivity 4: Growth Rings as Indicators of ClimateActivity 5: Radiation and Its Effects on SeedsActivity 6: Survival in Extreme ClimatesActivity 7: Upfolds and DownfoldsActivity 8: Making WavesActivity 9: A Trip Around the WorldActivity 10: Investigating DiatomiteActivity 11: Coal: What's My Rank?Activity 12: Tornado in a JarActivity 13: Identifying Metals and NonmetalsActivity 14: The Inside Story of PackagingActivity 15: Lenses that MagnifyActivity 16: Electrolytes and ConductivityActivity 17: Curds and WheyActivity 18: Cabbage ChemistryActivity 19: States of MatterActivity 20: Isotopes And Atomic Mass

Study Guide and ReinforcementChapter 1: The Nature of ScienceChapter 2: MatterChapter 3: MineralsChapter 4: RocksChapter 5: Earth's Energy and Mineral ResourcesChapter 6: Views of EarthChapter 7: Weathering and SoilChapter 8: Erosional ForcesChapter 9: Water Erosion and DepositionChapter 10: Plate TectonicsChapter 11: EarthquakesChapter 12: VolcanoesChapter 13: Clues to Earth's PastChapter 14: Geologic TimeChapter 15: AtmosphereChapter 16: WeatherChapter 17: ClimateChapter 18: Ocean MotionChapter 19: OceanographyChapter 20: Our Impact on LandChapter 21: Our Impact on Water and AirChapter 22: Exploring SpaceChapter 23: The Sun-Earth-Moon SystemChapter 24: The Solar SystemChapter 25: Stars and Galaxies

Reading and Writing Skills ActivitiesActivity 1Activity 2Activity 3Activity 4Activity 5Activity 6Activity 7Activity 8Activity 9Activity 10Activity 11Activity 12Activity 13Activity 14Activity 15Activity 16Activity 17Activity 18Activity 19Activity 20Activity 21Activity 22Activity 23Activity 24Activity 25Activity 26

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Chapter 3: Minerals · 2011. 4. 6. · minerals. A mineral is a naturally occurring, inorganic solid with a definite chemical composition and an orderly arrange-ment of atoms. About