Learning Objectives

Each statement represents the primary learning objective for the corresponding major heading within the chapter. After you complete the chapter, you should be able to:

• • 1.1List and describe the main characteristics that an Earth material must possess to be considered a mineral.

  • 1.2 Compare and contrast the three primary particles contained in atoms.

  • 1.3 Distinguish among ionic bonds, covalent bonds, and metallic bonds and explain how they form minerals.

  • 1.4 List and describe the properties used in mineral identification.

  • 1.5 List the common silicate and nonsilicate minerals and describe what characterizes each group.

Index of Mineral Images - a collection of images and information about EVERY known mineral

Concept Checks 1.1

1. List five characteristics of a mineral.

2. Based on the definition of a mineral, which of the following—gold, liquid water, synthetic diamonds, ice, and wood—are not classified as minerals?

3. Define the term rock. How do rocks differ from minerals?

Concept Checks 1.2

1. Make a simple sketch of an atom and label its three main particles. Explain how these particles differ from one another.

2. What is the significance of valence electrons?

Concept Checks 1.3

1. Explain the difference between an atom and an ion.

2. How does an atom become a positive ion or a negative ion?

3. Briefly distinguish between ionic, covalent, and metallic bonding and discuss the role that electrons play in each.

Concept Checks 1.4

1. Why is color not always a useful property in mineral identification? Give an example of a mineral that supports your answer.

2. What differentiates cleavage from fracture?

3. What is meant by a mineral’s tenacity? List three terms that describe tenacity.

4. Describe a simple chemical test that is useful in identifying the mineral calcite.

Concept Checks 1.5

1. List the eight most common elements in Earth’s crust.

2. Sketch the silicon–oxygen tetrahedron and label its parts.

3. What is the most abundant mineral in Earth’s crust?

4. What is the most common carbonate mineral?

5. List six common nonsilicate minerals and their economic uses.

1 Concepts In Review: Matter and Minerals 

1.1 Minerals: Building Blocks of Rocks

List and describe the main characteristics that an Earth material must possess to be considered a mineral.

Key Terms:

• • mineralogy

  • mineral

  • rock

• • Geologists use the word mineral to refer to naturally occurring inorganic solids that possess an orderly crystalline structure and a characteristic chemical composition.

  • Minerals are the building blocks of rocks. Rocks are naturally occurring masses of minerals or mineral-like matter such as natural glass or organic material.

1.2 Atoms: Building Blocks of Minerals

Compare and contrast the three primary particles contained in atoms.

Key Terms:

• • atom

  • nucleus

  • proton

  • neutron

  • electron

  • valence electron

  • atomic number

  • element

  • periodic table

  • chemical compound

• • Minerals are composed of atoms of one or more elements. All atoms consist of the same three basic ingredients: protons, neutrons, and electrons.

  • The atomic number represents the number of protons found in the nucleus of an atom of a particular element.

  • Protons and neutrons have approximately the same size and mass, but protons are positively charged, whereas neutrons have no charge.

  • Electrons weigh only about 1/2000 as much as protons or neutrons. They occupy the space around the nucleus, where they form a structure consisting of several distinct energy levels called principal shells. The electrons in the outermost principal shell, called valence electrons, are responsible for the bonds that hold atoms together to form chemical compounds.

  • The periodic table is organized so elements with the same number of valence electrons form a column or group consisting of elements that tend to behave similarly.

1.3 How Atoms Bond to Form Minerals

Distinguish among ionic bonds, covalent bonds, and metallic bonds and explain how they form minerals.

Key Terms:

• • chemical bond

  • octet rule

  • ion

  • ionic bond

  • covalent bond

  • metallic bond

• • Chemical bonds form when atoms are attracted to other atoms, leading to the transfer or sharing of valence electrons. The most stable arrangement for most atoms is to have eight electrons in the outermost principal shell, called the octet rule.

  • To form ionic bonds, atoms of one element give up one or more valence electrons to atoms of another element, forming positively and negatively charged atoms called ions. The ionic bond results from the attraction between oppositely charged ions.

  • Covalent bonds form when adjacent atoms share valence electrons.

  • Metallic bonds involve extensive sharing of the valence electrons, such that the electrons move freely through the substance.

  • Minerals form in various ways. They may precipitate out of a solution, forming bonds as water they are suspended in evaporates. As molten rock cools, the atoms form bonds with other atoms to produce a crystalline material. And some marine organisms extract ions from the surrounding seawater and secrete skeletal material, usually made of calcium carbonate or silica.

QUESTION: Match the diagrams labeled A–C with the type of bonding each illustrates: ionic, covalent, or metallic. What are the distinguishing characteristics of each type of bonding?

1.4 Properties of Minerals

List and describe the properties used in mineral identification.

Key Terms:

• • diagnostic property

  • ambiguous property

  • luster

  • color

  • streak

  • crystal shape (habit)

  • hardness

  • Mohs scale

  • cleavage

  • fracture

  • tenacity

  • density

  • specific gravity

• • Luster is a mineral’s ability to reflect light. Transparent, translucent, and opaque describe the degree to which a mineral can transmit light.

  • Color can be unreliable for mineral identification. A more reliable identifier is streak, the color of the powder generated by scraping a mineral against a porcelain streak plate.

  • Crystal shape, also called crystal habit, is often useful for mineral identification.

  • Variations in the strength of chemical bonds give minerals properties such as resistance to being scratched, called hardness (measured by the Mohs scale) and resistance to deforming stresses, called tenacity (which could be brittle breakage, bending, or malleable deformation).

  • Cleavage, the preferential breakage of a mineral along planes of weakly bonded atoms, is very useful in identifying minerals.

  • The amount of matter packed into a given volume determines a mineral’s density. To compare the densities of minerals, mineralogists use a related quantity, known as specific gravity, which is the ratio between a mineral’s density and the density of water.

  • Diagnostic properties are characteristics used for identifying minerals. Certain properties, such as smell, taste, feel, reaction to hydrochloric acid, magnetism, and double refraction, are diagno

QUESTION: Determine which of these specimens exhibit a metallic luster and which have a nonmetallic luster. 

1.5 Mineral Groups

List the common silicate and nonsilicate minerals and describe what characterizes each group.

Key Terms:

• • rock-forming mineral

  • economic mineral

  • silicate

  • nonsilicate

  • silicon–oxygen tetrahedron

  • light silicate mineral

  • potassium feldspar

  • plagioclase feldspar

  • quartz

  • muscovite

  • clay mineral

  • dark silicate mineral

  • olivine

  • augite

  • hornblende

  • biotite

  • garnet

  • calcite

  • dolomite

  • halite

  • gypsum

• Silicate minerals have a basic building block in common: a small pyramid-shaped structure called the silicon–oxygen tetrahedron, which consists of one silicon atom surrounded by four oxygen atoms. Neighboring tetrahedra can share some of their oxygen atoms, causing them to develop long chains, sheet structures, and three-dimensional networks.

• Silicate minerals are the most common mineral class on Earth. They are subdivided into minerals that contain iron and/or magnesium (dark silicate minerals) and those that do not (light silicate minerals). The light silicate minerals are generally light in color and have relatively low specific gravities. Feldspar, quartz, muscovite, and clay minerals are examples. The dark silicate minerals are generally dark in color and relatively dense. Olivine, pyroxene, amphibole, biotite, and garnet are examples.

• Nonsilicate minerals include oxides, which contain oxygen ions that bond to other elements (usually metals); carbonates, which have CO32−CO32− as a critical part of their crystal structure; sulfates, which have SO42−SO42− as their basic building block; and halides, which contain a nonmetal ion s

Give It Some Thought

1. Using the geologic definition of mineral as your guide, determine which of the items in this list are minerals and which are not. If something in this list is not a mineral, explain.

   1. Gold nugget

   2. Seawater

   3. Quartz

   4. Cubic zirconia

   5. Obsidian

   6. Ruby

   7. Glacial ice

   8. Amber

2. Assume that the number of protons in a neutral atom is 92 and the atomic mass is 238.01. (Hint: Refer to the periodic table in Figure 1.5 to answer this question.)

   1. What is the name of the element?

   2. How many electrons does it have?

3. Gold has a specific gravity of almost 20. A 5-gallon bucket of water weighs 40 pounds. How much would a 5-gallon bucket of gold weigh?

4. Examine the accompanying photo of a mineral that has several smooth, flat surfaces that resulted when the specimen was broken.

   1. How many flat surfaces are present on this specimen?

   2. How many different directions of cleavage does this specimen have?

   3. Do the cleavage directions meet at 90-degree angles?

5. Each of the following statements describes a silicate mineral or mineral group. In each case, provide the appropriate name:

   1. The most common member of the amphibole group

   2. The most common light-colored member of the mica family

   3. The only common silicate mineral made entirely of silicon and oxygen

   4. A silicate mineral with a name based on its color

   5. A silicate mineral characterized by striations

   6. Silicate minerals that originate as a product of chemical weathering

6. What mineral property is illustrated in the accompanying photo?

Do an Internet search to determine which minerals are used to manufacture the following products:

1. Stainless steel utensils

2. Cat litter

3. Tums brand antacid tablets

4. Lithium batteries

5. Aluminum beverage cans