Minerals are inorganic crystalline substances formed through geological processes. They are studied in mineralogy. Crystals have orderly atomic arrangements. Rocks are aggregates of two or more minerals and are studied in petrology. There are three rock types: igneous rocks form from cooling magma, sedimentary rocks form through weathering or biological/chemical processes, and metamorphic rocks form from the transformation of other rocks under heat and pressure. The rock cycle illustrates the formation and transformation of these three rock types over time through weathering, erosion, and other geological processes.

1. An Introduction to
Geology

2. Minerals
o Minerals are natural
compounds formed through
geologic processes.
o They are inorganic substances
they do not contain carbon)
and have a crystalline
structure.
o The study of minerals is called
mineralogy.

3. Crystal Structures
A crystal structure is the orderly
arrangement of atoms within a mineral.

4. Rocks
 Rocks are aggregates of 2 or
more minerals.
 Petrology is the study of
rocks.
 Rocks can be igneous,
sedimentary, or
metamorphic.

5. Igneous Rocks
Granite is an igneous rock
o Igneous rocks are formed when molten rock
(magma) cools and solidifies, with or without
crystallization, either below the surface as intrusive
(plutonic) rocks or on the surface as extrusive
(volcanic) rocks.

6. Sedimentary Rock
Sedimentary rock is formed in three main ways:
Limestone and shale are both types of
sedimentary rock
1. by the deposition of the
weathered remains of other
rocks (known as clastic
sedimentary rocks)
2. by the deposition of the
results of biogenic activity
3. by precipitation from
solution

7. Metamorphic Rock
 Metamorphic rock is the result of the transformation of
a pre-existing rock type.
 The pre-existing rock type is called the protolith.
 Pressure and heat physically and chemically change the
protolith.
 Metamorphic means "change in form“.
Slate is a type of
metamorphic rock

8. The Rock Cycle

9. Erosion
• Erosion is the displacement of
solids (soil, mud, rock, and other
particles) because of wind,
water, ice, gravity, or living
organisms.
• Bioerosion is erosion that is the
result of humans or other living
organisms.
• Deforestation, overgrazing, and
road or trail building are human
activities that can lead to
erosion.

10. Weathering
• Weathering is the process of decomposition and/or
disintegration of rocks, soils and their minerals
through natural, chemical, and biological processes.