Minerals are naturally occurring inorganic solids with a crystalline structure. They are composed of elements or compounds and form in various environments through processes like heat, volcanic activity, and water/pressure interactions. Key properties used to identify minerals include color, luster, streak, cleavage, fracture, hardness, and density. The most common minerals are silicates containing silicon and oxygen or nonsilicate minerals without these elements.

1. 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:

2. Questions
 Is it a solid?
 Is it formed in nature?
 Does it have a crystalline structure?
 Is it nonliving material?

3. What are they made of?
 Mineralsare made of elements. Each element
is made of only one kind of atom.
 Most minerals are made of compounds of
different elements.

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

5. Types of Minerals
 SilicateMinerals-Minerals that contain a
combination of the elements silicon and
oxygen.
 NonsilicateMinerals-Minerals that do not
contain compounds of silicon and oxygen.

6. 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.

7. 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.

8. Identifying Cont.
 Streak-thecolor 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.

9. 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.

10. 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