Minerals

 

THE BIG IDEA: Minerals are basic building blocks of Earth. 

 

2.1 KEY CONCEPT: Minerals are all around us.

 

Minerals have four characteristics. (p 43-44)

1.        They form in nature.

2.                They are solids.

3.                They have a definite chemical makeup.

4.                They have a crystal structure.

 

Minerals are not the same as rocks because rocks only have two of these characteristics.

1.     Rocks are solids.

2.         Rocks form naturally.

Minerals are formed in nature. (p. 44)

Minerals form in many ways.

·      Halite

-     Used to make table salt.

-     Formed when water evaporates in a hot, shallow part of the ocean (leaving its salt behind).

 

 

 

·      Coal

-     Anthracite (also called “hard coal”)

-     Forms when great pressures developed in folded rock during the creation of mountain ranges.

-     Has the highest energy content of all the coals and is used to generate electricity.

 

 

 

-     Found in the Appalachian Mountains.

Minerals are solids. (p. 45)

·      Liquids and gases are not minerals. 

·      Sometimes the solid form is a mineral (water is not a mineral but ice is). 

Minerals have a definite chemical makeup.

·      Made of atoms of certain elements.

-     Element- A substance that has all the same type of atoms.

-     Atom- The smallest particle that an element can be divided into.

*Everything you can see or touch is made up of atoms.

*Most minerals are compounds; that is they are made of several elements.

Minerals have a crystal structure. (p. 46)

·      Crystal- A solid in which the atoms are arranged in an orderly, repeating three-dimensional pattern.

·      Each mineral has its own type of crystal structure. 

·      In nature, perfect crystals are rare.  They must have free space to grow. 

·      There are six crystal groups.

 

 

Minerals are grouped according to composition.

·      Scientists classify minerals into groups based on their chemical makeups. 

·      Most common group:  silicates (includes quartz, feldspar, and mica).  See chart

-     All silicates contain oxygen and silicon- the most common elements of the Earth’s crust.

·      There are thousands of minerals, but only about 30 are common in the Earth’s crust.

-     They are the rock-forming minerals.

·      Second most common group: carbonates.

-     All contain carbon and oxygen joined together.  Example: Calcite.  See chart

 

 

 

Review Questions:

1. What are the four characteristics of a mineral?

 

2. How do scientists classify minerals?

 

3. What is the most common group of minerals?

 

4. Can water be classified as a mineral?  How about ice?  Why or why not?

 

5. What is a crystal? 

 

6. List the six crystal groups.

 

7. Why are rocks not classified as minerals?