Chapter 3Minerals

Lesson 1What is a mineral?

Pages 76-84

Chapter Introduction

What are minerals and why are they useful?

http://www.redorbit.com/news/video/education_1/1112810933/what-is-a-mineral/

Chapter Introduction

SS#1 Sept. 24, 2013

Do you agree or disagree? Agree Disagree

A mineral is anything solid on Earth.

Some minerals form when water evaporates from Earth’s surface.

What is a mineral?

crystal solid chemical substance with a regular, repeating arrangement of its atoms

crystallization when particles dissolved in a liquid solidify to form crystals

lava molten rock that erupts onto Earth’s surface

magma molten rock material under Earth’s surface

Silicate a mineral group that has silicon and oxygen in its crystal structure

I can explain:• What is a mineral? (5 characteristics)• What the 6 crystal shapes are?• How minerals form? (3 ways plus an example)• What the common rock-forming minerals are?

(2 groups plus an example)

What is a mineral?

Lesson 1 Notes – What is a mineral?• Minerals are naturally occurring, inorganic (non-living) solids

that have a definite chemical composition and join together in an orderly crystal structure.

Mineralsnaturally occurring

inorganic

solidsdefinite chemical

composition

orderly crystal structure

• Minerals occur in many different shapes.

• When a crystal forms under the right conditions and has time to grow, it will develop a characteristic crystal shape.

• Most of the time, minerals grow in tiny clusters.

The Structure of Minerals

Crystal Shapes –HexagonalFour axes, three are equal in length and lie at an angle of 120° from each other.

Triclinic 3 axis, all unequal and none at 90° angles.

Orthorhombic All axis unequal in length, and 90° degrees from each other.

Crystal Forms –Monoclinic All axis unequal in length. Two of them are at right angles to each other, while the third is lies at an angle other than 90°.

Tetragonal Three axes, two are equal in length, one is unequal.)

Isometric/Cubic All three axes are equal in length and at 90° degrees from each other.

• Minerals can crystallize from either hot or cool solutions.

• As water evaporates from a cool solution in a dry environment, solids crystallize out of the water and form minerals.

Example – halite

How do minerals form?

• Hot solutions are made when water flows through cracks in the earth’s crust into deep and hot environments.• Sometimes hot solutions carry large concentrations

of dissolved solids that eventually become valuable mineral deposits.

Example - gold

How do minerals form? (cont.)

• Minerals can also form from magma. Magma is molten material stored beneath Earth’s surface.

• When magma erupts on or near Earth’s surface, it is called lava or ash.

How do minerals form? (cont.)

• As lava above ground cools small crystals form quickly on or near Earth’s surface.

• Also as magma cools and crystallizes slowly below Earth’s surface, atoms and ions arrange themselves and form large mineral crystals.

Example – Quartz

How do minerals form? (cont.)

• The common rock-forming minerals are composed of combinations of elements that are abundant in Earth’s crust.

• Oxygen and silicon are the two most abundant elements in the crust.

The Structure of Minerals

The two main families of rock-forming minerals are the silicates and the nonsilicates.

• A silicate is a member of the mineral group that has silicon and oxygen in its crystal structure.

Example: Quartz, Feldspar, Olivine and Mica

• Nonsilicate minerals do not contain silicon.Example: Calcite and Halite

The Structure of Minerals (cont.)

• A mineral is a naturally occurring, inorganic solid with a definite chemical composition and crystalline form.

• Crystal shape reflects the internal arrangement of atoms or ions.

• The most common rock-forming minerals are silicates.

Lesson 1 – LR1

A. definiteB. indefiniteC. unstableD. stable

What type of chemical composition do minerals have?

Lesson 1 – LR2

A. mantleB. coreC. crustD. oceans

The common rock-forming minerals are composed of combinations of elements found in which part of the Earth?

A. evaporationB. disintegrationC. crystal growthD. crystallization

Which process occurs when particles dissolved in a liquid or gas solidify and form crystals?

1. A mineral is anything solid on Earth.

2. Some minerals form when water evaporates from Earth’s surface.

Do you agree or disagree?