Defines a mineral, describes how minerals form and identifies the most common elements in Earth's crust

1. Section 4.1
What is a Mineral?
Glencoe Earth Science
Geology, the Environment and the Universe

2. Introduction
Earth’s crust is composed of about 3000 minerals
Minerals help form rocks and shape Earth’s surface

3. Mineral Characteristics
• A mineral is a naturally occurring, inorganic solid with specific
chemical composition and definite crystalline structure.
• Naturally Occurring: The are made in nature not in a lab or
factory.
• Inorganic: They aren’t alive and never have been alive. For
example salt is a mineral but sugar isn’t because sugar comes
from a plant which is a living thing.
• Solid: Has a definite shape and volume.
• Chemical composition: Some are made from single elements
like copper, silver and sulfur. The majority are made of
compounds (two or more different types of elements). When
the mineral is formed of a compound the ratio of each
element is always the same.

4. Mineral Characteristics Cont.
• Definite crystalline
structure: A crystal is a
solid in which the
atoms are arranged in
repeating patterns.
• Crystals may take the
shape of 6 major
crystal systems: cubic,
tetragonal, hexagonal,
orthorhombic,
monoclinic and triclinic

5. Examples of How Crystals
Grow
Sample of crystal that grew in an Sample of crystal that grew in a
open space restricted space

6. Minerals From Magma
• Minerals can form from the cooling of magma
• Magma is molten material found beneath Earth’s Surface.
• Because of it’s density, magma is forced up to the cooler layers of
Earth’s surface.
• The type and amount of elements in the magma will determine
what type of minerals will form.
• The rate of the cooling will determine the size of the mineral
crystals.
• Magma that cools slowly will form larger crystals because the
atoms have more time to rearrange
• Magma that cools quickly will form smaller crystals because the
atoms don’t have as much time to move around.

7. Minerals That Form From
Magma
Granite Chromite

8. Minerals From Solution
Once a given volume of water can no longer dissolve a solid, the If elements dissolve in a supersaturated solution minerals can
water becomes saturated with that solid. In nature if the water
becomes supersaturated, or overfilled, with another substance, form when the water evaporates
mineral crystals may begin to drop out of the solution

9. Mineral Groups
• Silicates
• Made up of silicon and oxygen (one silicon atom is bonded to
three oxygen atoms)
• They are 96% of minerals found in Earth’s crust.
• Common examples are feldspar and quartz
• Carbonates
• Minerals composed of one or more metallic elements combined
with CO2 (Carbon Dioxide)
• Some have distinct colors (malachite and azurite)
• Found in rocks like limestone, coquina and marble

10. Mineral Groups Cont.
• Oxides
• Compounds of oxygen and a metal
• Examples include hematite and magnetite
• Other Mineral Groups include:
• Native Elements
• Hydroxides
• Halides
• Sulfates
• Sulfites

11. Silicates

12. Carbonates

13. Oxides