Minerals

Properties of Minerals

How Minerals Form

Using Mineral Resources

Table of Contents

Minerals

What Is a Mineral?

A mineral is a naturally occurring, inorganic solid that has a crystal structure and a definite chemical composition.

- Properties of Minerals

Minerals

5 common mineral characteristics

1. Naturally occurring

2. Inorganic

3. Solid

4. Definite chemical composition (i.e. SiO2)

5. Crystal structure

*A mineral must have all 5 of these characteristics!

*Otherwise the substance is not considered a mineral!

Minerals

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.)

Minerals

Calculating Density 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

Minerals

Mineral Density

Use the line graph of the mass and volume of pyrite samples to answer the questions.

- Properties of Minerals

Minerals

Mineral Density

50 g; 10 cm3

Reading Graphs:

What is the mass of Sample B? What is the volume of Sample B?

- Properties of Minerals

Minerals

Mineral Density

5 g/cm3

Calculating:

What is the density of Sample B?

- Properties of Minerals

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

Minerals

Mineral Density

5 g/cm3

Calculating:

What is the density of Sample C?

- Properties of Minerals

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

Minerals

Mineral Density

8 g

Predicting:

A piece of pyrite has a volume of 40 cm3. What is its mass?

- Properties of Minerals

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

Minerals

Identifying Minerals

- Properties of 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.

Minerals Moh’s Hardness Scale

Minerals

OutliningAn 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.

Properties of Minerals

I. What Is a Mineral?A. Naturally OccurringB. InorganicC. SolidD. Crystal StructureE. Definite Chemical

CompositionII. Identifying Minerals

A. ColorB. StreakC. LusterD. DensityE. HardnessF. Crystal SystemsG. Cleavage and FractureH. Special Properties

- Properties of Minerals

Minerals

End of Section:Properties of

Minerals

Minerals

• Minerals form by the crystallization of magma and lava

• Minerals also form from crystallization of materials dissolved in water

- How Minerals Form

Minerals

Minerals

Minerals Generally Form in Two Ways:

1. Minerals can form on the surface through evaporation of solutions containing dissolved minerals.

2. Minerals can also form beneath the surface when dissolved elements and compounds leave a hot water solution or when magma cools and hardens.

Minerals Terminology

Geodes are hollow rocks that contain crystals inside of them

Crystallization is the process where atoms are arranged to form a material with a crystal structure

*Crystallization occurs in two ways:

1. From magma slow cooling beneath the surface resulting in larger crystals and from lava quickly cooling resulting in smaller crystals (change from liquid to solid state)

2. 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)

Minerals

Asking QuestionsBefore 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.

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.

Questions Answers

- How Minerals Form

Minerals

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!

Minerals

Producing Metals from Minerals

• Rocks contain many minerals (including metals) and must be 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:

1. Strip mines

2. Open pit mines

3. Shaft mines

Minerals

Strip Mines Change the Landscape Forever!

Minerals

Open Pit Mines

Minerals

Shaft Mine

Minerals

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.

- Using Mineral Resources

Minerals

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.

Example: Steel is produced by adding carbon to iron.

*Further processing can result in stronger stainless steel by adding the elements Manganese, Nickel, and Chromium

Minerals

What You Know

What You Learned

Using Prior KnowledgeBefore 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.

1. The gems used in jewelry are minerals.2. Metals come from Earth.

1. Minerals are also the source of metals and other useful materials, like quartz and gypsum.

2. Most metals come from ores, which are mined and smelted before the metals can be used.

- Using Mineral Resources

Minerals

End of Section:Using Mineral

Resources

Minerals

Graphic Organizer

Hematite Brick

Naturally occurring

Crystal structure

Definite chemical

composition

Solid or inorganic

Inorganic or solid

Human-made

No crystal structure

Chemical composition

varies

Minerals

End of Section:Graphic Organizer