Science, Grade 6


Table Of Contents: Minerals

1. What Is a Mineral?

2.1. Minerals Are Naturally Occurring
A substance must meet four criteria to be classified as a mineral. First, it must be naturally occurring. Minerals are always formed by natural processes, such as cooling molten lava.
2.2. Minerals Are Inorganic
Minerals are inorganic, nonliving substances. They cannot be made up of any material that was once a living organism.
2.3. Minerals Are Solid Substances
A mineral must be a solid substance. It has volume and shape, and is not a liquid or gas.
2.4. Minerals Have a Crystal Structure
Every mineral has a specific crystal structure with particles arranged in a repeated pattern. A mineral's atomic structure determines its crystal structure.
2.5. Is a Rock a Mineral?
A rock is not a mineral. A rock is composed of one or more minerals and sometimes contains organic material. Coal is considered a rock.

2. Properties of Minerals

3.1. How Are Minerals Identified?
Minerals are identified by their physical properties. There are a number of properties that can be tested.
3.2. Mineral Hardness
A mineral's hardness is determined by comparing it to the minerals in the Mohs Hardness Scale. For example, halite is harder than gypsum because it will scratch gypsum. But, when halite is rubbed against calcite, it gets scratched. That means halite has a hardness between 2 and 3.
3.3. Mineral Color
The color of a mineral is easy to see but is not always the best way to identify it. Many minerals are the same color, and some minerals can change color if they are exposed to different conditions, like air or water.
3.4. Mineral Streak Color
Streak is the color of a mineral when it is crushed to a powder. If you rub a mineral across a piece of unglazed porcelain, a streak is seen. Minerals harder than a 7 on the Mohs Hardness Scale do not leave a streak.
3.5. Mineral Luster
Luster is a description of how light reflects off of a mineral. Some of the luster descriptions are metallic, glassy, greasy and dull.
3.6. Specific Gravity of a Mineral
Specific gravity is a measure of a mineral's density. Density is determined by comparing the mass of a mineral to the mass of an equal volume of water. Volume is measured by dropping a mineral sample in water and looking at the amount of displacement. A scale is used to measure mass.
3.7. Mineral Crystal System
Every mineral forms a specific crystal shape and belongs to one of several different crystal systems. Each system is determined by the internal arrangement of the molecules in a mineral.
3.8. Cleavage or Fracture of a Mineral
A mineral that breaks apart in flat planes has cleavage. A mineral that breaks unevenly along irregular surfaces has fracture. There are several different types of fracture.
3.9. Mineral Special Properties
Some minerals have unique physical properties. For example, calcite glows under ultraviolet light, and magnetite is magnetic.
3.10. Mineral Properties Table
If you have a sample of an unknown mineral, you can use all of these physical properties to identify it.

3. Pause and Interact

4.1. Review
Use the whiteboard tools to complete the activity.
4.2. Sequence: Mohs Hardness Scale
Follow the onscreen instructions.

4. How Do Minerals Form?

5.1. Where Do Minerals Form?
Minerals form in a wide variety of geologic environments.
5.2. Mineral Metamorphism
Some minerals form as a result of intense heat and pressure created during metamorphism. Talc is an example of a metamorphic mineral.
5.3. Cooling Magma Forms Minerals
Other minerals crystallize from magma as it cools. Examples include tourmaline, feldspar and quartz.
5.4. Evaporation and Precipitation Form Minerals
Another group of minerals forms when ocean water evaporates. The most common mineral to form this way is halite (rock salt).
5.5. Hot Water Solutions Form Minerals
Some minerals form in hot water solutions. Ground water that is heated by magma causes elements and compounds to dissolve into a hot liquid. When the liquid cools, minerals such as gold and copper are formed.

5. Mineral Resources

6.1. Ore Deposits
Rock that contains metal or important minerals is called ore. Large amounts of ore are called ore deposits.
6.2. Mining Methods
Several methods of mining are used to remove rocks and minerals from the ground. When ore is close to the earth's surface, strip mining and open pit mining methods are used.
6.3. Shaft Mines
Shaft mines are dug when the ore deposits are deep below the surface.
6.4. Processing Ore
Nearly all mineral resources need to be processed after they are mined. A process called smelting mixes the ore with other substances and then melts the mixture to separate the useful minerals and metal.

6. Mining and the Environment

7.1. Mining and Environmental Issues
Mining can create significant environmental problems. It can destroy habitats and produce waste products that pollute the land, water and air.
7.2. Mining and Land Reclamation
Land reclamation is a top priority of the mining industry today. It involves bringing in new topsoil and planting trees, grasses and other native plants.
7.3. Mineral Reserves and Recycling
The Earth's mineral reserves are sufficient to supply most of our needs, but in many cases recycling previously used materials is more efficient than producing them from ore.

7. Use of Minerals

8.1. Importance of Minerals
Minerals are found in products we use every day. In our modern civilization, materials made from minerals are of major industrial and economic importance.
8.2. Using Minerals in Homes
Think about the materials involved in building a new home. Gypsum is used to make wallboard and cement. Steel is an iron mixture used for framework, furniture and appliances.
8.3. Using Minerals in a Television
A television alone contains 35 or more mineral-made materials. For example, quartz is used for making glass and silicon chips, while copper is made into wires.
8.4. Gemstones
Gemstones are minerals that are valued for their rarity and beauty. They are primarily used for jewelry and decoration, but some are useful in making mechanical parts.

8. Pause and Interact

9.1. Review
Use the whiteboard tools to complete the activity.
9.2. Mineral Uses
Follow the onscreen instructions.

9. Vocabulary Review

10.1. Minerals Vocabulary Matching
In this activity you will match cards that show terms, definitions and images. A card will be chosen at random and highlighted. Use the up and down arrows to line up the correct matches in the other columns. Then click Check Matches.

10. Virtual Investigation

11.1. Mineral Identification
In this virtual investigation you will identify minerals by observing and testing their physical properties. After gathering data for an unknown mineral, you will refer to an identification chart to determine the mineral's identity.

11. Assessment

12.1. Minerals