Minerals of the Earth’s Crust

Mineral- it is a naturally formed, inorganic solid with a crystalline structure.

How do you know if you have a mineral?

-If you cannot answer Yes to the all of the following questions then you do not have a mineral:

Questions

Is it a solid? Is it formed in nature? Does it have a crystalline structure? Is it nonliving material?

What are they made of?

Minerals are made of elements. Each element is made of only one kind of atom.

Most minerals are made of compounds of different elements.

Crystals

They are solid, geometric forms of minerals produced by a repeating pattern of atoms that is present throughout the mineral.

Types of Minerals

Silicate Minerals-Minerals that contain a combination of the elements silicon and oxygen.

Nonsilicate Minerals-Minerals that do not contain compounds of silicon and oxygen.

Identifying Minerals

There are many ways to identify a mineral. Some of the ways are to look at their color, luster, streak, cleavage, fracture, hardness, and density.

Identifying Cont.

Color-similar minerals can come in different colors. Color is not a reliable indicator of a mineral’s identity.

Luster-The way a surface reflects light.

Streak-the color of a mineral in powdered form. Cleavage-The tendency of some minerals to

break along flat surfaces. Fracture-The tendency of some minerals to

break unevenly along curved or irregular surfaces.

Identifying Cont.

Identifying Cont.

Hardness-A mineral’s resistance to being scratched.

Density-A measure of how much matter there is in a given amount of space.

Formation of Minerals

Almost all minerals can be found in the Earth’s crust.

They are formed in many different environments.

- Heat - Volcanic activity - Presence of ground water - Pressure