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?