Properties used to identify a mineral • Color(easily observed but not always accurate) • Streak (color of a mineral in powder form) • Luster (how light is reflected from the surface of a mineral) • Density (mass / volume) • Hardness (moh’s hardness scale 1-10) • Crystal system (atom arrangement gives the mineral it’s shape) • Cleavage (mineral that splits along flat surfaces) • Fracture (breaks apart in uneven pattern) • Special properties (magnetism, fluorescence, reactivity, etc.)

To calculate the density of a mineral, divide the mass of the mineral sample by its volume. Density = Mass/Volume For example, if a sample of olivine has a mass of 237 g and a volume of 72 cm3, then the density is 237 g/72 cm3 = 3.3 g/cm3 Practice Problem A sample of calcite has a mass of 324 g and a volume of 120 cm3. What is its density? 324 g ÷ 120 cm3 = 2.7 g/cm3 - Properties of Minerals Calculating Density

- Properties of Minerals Mineral Density • Use the line graph of the mass and volume of pyrite samples to answer the questions.

50 g; 10 cm3 Reading Graphs: What is the mass of Sample B? What is the volume of Sample B? - Properties of Minerals Mineral Density

5 g/cm3 Calculating: What is the density of Sample B? - Properties of Minerals Mineral Density

100 g; 20 cm3 Reading Graphs: What is the mass of Sample C? What is the volume of Sample C? - Properties of Minerals Mineral Density

5 g/cm3 Calculating: What is the density of Sample C? - Properties of Minerals Mineral Density

The density of samples B and C is the same. Comparing and Contrasting: Compare the density of Sample B to that ofSample C. - Properties of Minerals Mineral Density

8 g Predicting: A piece of pyrite has a volume of 40 cm3. What is its mass? - Properties of Minerals Mineral Density

No; density does not depend on size. Larger samples have more mass, but the ratio between mass and volume is constant. Drawing Conclusions: Does the density of a mineral depend on the size of the mineral sample? Explain. - Properties of Minerals Mineral Density

- Properties of Minerals Identifying Minerals • The crystals of each mineral grow atom by atom to form that mineral’s particular crystal structure. Geologists classify these structures into six groups based on the number and angle of the crystal faces.

Moh’s Hardness Scale

- Properties of Minerals Outlining Properties of Minerals • An outline shows the relationship between major ideas and supporting ideas. As you read, make an outline about the properties of minerals. Use the red headings for the main topics and the blue headings for the subtopics. • What Is a Mineral? • Naturally Occurring • Inorganic • Solid • Crystal Structure • Definite Chemical Composition • Identifying Minerals • Color • Streak • Luster • Density • Hardness • Crystal Systems • Cleavage and Fracture • Special Properties

End of Section:Properties of Minerals

- How Minerals Form Where Minerals Form • Minerals can form on the surface through evaporation of solutions containing dissolved minerals. Minerals can form beneath the surface when dissolved elements and compounds leave a hot water solution or when magma cools and hardens.

Terminology • Geodes are hollow rocks that contain crystals inside • Crystallization is the process where atoms are arranged to form a material with a crystal structure • *Crystallization occurs in two ways: • From magma slow cooling beneath the surface resulting in larger crystals and from lava quickly cooling resulting in smaller crystals (liquid to solid state) • From solutions (mixture where one substance dissolves in another). • *crystallization occurs when elements and compounds that are dissolved in water leave a solution • This occurs either through evaporation or from hot water solutions representing a vein (a mineral deposit found in surrounding rock)

- How Minerals Form Asking Questions • Before you read, preview the red headings. In a graphic organizer like the one below, ask a how or what question for each heading. As you read, write answers to your questions. Questions Answers How do minerals form from magma? They form when magma cools and crystals grow. How do minerals form from solutions? They form when solutions evaporate or cool.

Using Mineral Resources • Minerals are the source of gemstones, metals, and a variety of materials used to make many products. • Gemstones are hard and colorful minerals with a glassy luster. • Metals typically are not as hard as gemstones, but can be stretched out and molded without breaking. • Minerals can be found everywhere…even in the foods you eat!

Producing Metals from Minerals • Rocks contain many minerals (including metals) and must be processed to removed from the ground and then processed to extract the metal. • An ore is a metal or other useful mineral that can be sold for a profit. • A prospector is a person who searches for ores to mine. • A miner is a person who actually extracts the ores for sale at a later time. • There are three type of mines: • Strip mines • Open pit mines • Shaft mines

- Using Mineral Resources Producing Metals From Minerals • In the process of smelting, an ore is mixed with other substances and then melted to separate the useful metal from the other elements the ore contains.

Further Processing of Metals • Impurities are removed and or additional elements can be added to make a metal stronger. • An alloy is a mixture of two or more elements with at least one of the elements being a metal. • Examples: Steel is produced by adding carbon to iron. Further processing can result in stronger stainless steel by adding the elements Manganese, Nickel, and Chromium.

- Using Mineral Resources Using Prior Knowledge • Before you read, look at the section headings and visuals to see what this section is about. Then write what you know about mineral resources in a graphic organizer like the one below. As you read, write what you learn. What You Know The gems used in jewelry are minerals. Metals come from Earth. What You Learned Minerals are also the source of metals and other useful materials, like quartz and gypsum. Most metals come from ores, which are mined and smelted before the metals can be used.

- Using Mineral Resources Rubies • Click the Video button to watch a movie about rubies.

- Using Mineral Resources Producing Aluminum • Click the Video button to watch a movie aboutproducing aluminum.

- Using Mineral Resources Links on Mining Minerals • Click the SciLinks button for links on mining minerals.

End of Section:Using Mineral Resources

Graphic Organizer Hematite Brick Naturally occurring Human-made Solid or inorganic Crystal structure No crystal structure Inorganic or solid Definite chemical composition Chemical composition varies

End of Section:Graphic Organizer

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