LAB

Mineral Identification

What you’ll learn

•Describe physical properties used to

identify minerals.

• Identify minerals using physical

properties such as hardness and streak.

Common uses of Rocks and

Minerals

• Have you ever used a Mineral?

• YES!!!!!!!

• The by-products of Minerals are all

around us.

Introduction

• Many of the items used in our homes

and in industry are made of materials

that were mined from the ground.

• There are thousand of known minerals .

• It is estimated that every person in the

USA will use more than a million

pounds of rocks, minerals and metals

during their lifetime.

Objectives

• Students will complete tests and

observations to identify different

minerals

Materials and Methods

• Samples of minerals

• Water

• Nail

• Penny

• Streak plate

• Magnifying lenses

Important Physical Properties

• Color

• Hardness

• Luster

• Specific gravity

• Streak

• Cleavage and fracture

• Interaction with light

We will use: Physical Properties

• Hardness

• Color

• Luster

• Streak

• Cleavage and fracture

• Interaction with light

Color

• The color of the mineral helps you with

identification, but sometimes, the same

mineral have different colors, so color

can’t be the only property used to identify

a mineral.

Luster

• It is the way a mineral reflects light.

• Either metallic or nonmetallic

Light Interaction - Put the

mineral on top of your book. If it

is:

• Opaque – no light pass through the mineral. You can’t see through

• Translucent – some light can pass through, but you can’t see through the mineral

• Transparent – light rays can pass through the mineral and you can see letters from the book right through it.

Streak

• Rub a mineral across a

piece of porcelain tile.

• a streak of powdered

mineral is left behind.

• The color of the streak

will help you identify

the mineral, because

sometimes is different

than the color of the

mineral.

Cleavage/ Fracture - the way a

mineral breaks

• Minerals that break along smooth, flat

surfaces have cleavage.

• Minerals that breaks uneven, rough, or

jagged surfaces have fracture.

Hardness of a Mineral

• It is defined by how easily a

mineral can be scratched by

another mineral or other materials

• The Mohs scale can be used to

compare the hardness of different

materials and the mineral being

identified.

Mohs Scale – Ex: if a mineral can be scratched

by a steel knife, its hardness is 5 or lower.

Mohs Hardness Scale

Mineral

Talc

Gypsum

Calcite

Fluorite

Apatite

Feldspar

Quartz

Topaz

Corundum

Diamond

Rating

1 Softest known mineral. It flakes easily when

scratched by a fingernail.

2 A fingernail can easily scratch it.

3 A fingernail cannot scratch it, but a copper

penny can.

4 A steel knife can easily scratch it.

5 A steel knife can scratch it.

6 Cannot be scratched by a steel knife, but it

can scratch window glass.

7 Can scratch steel and hard glass easily.

8 Can scratch quartz.

9 Can scratch topaz.

10 Hardest known mineral. Diamond can cut or

scratch all other substances.

Testing Method