Mineral IdentificationMineral Identification

What you’ll learn

•Describe physical properties used to identify minerals.

Common uses of Rocks and Minerals

• Have you ever used a Mineral?

• YES!!!!!!!

• 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.

Important Physical Properties Important Physical Properties used in the identification of used in the identification of

minerals minerals • Color

• Hardness

• Luster

• Specific gravity

• Streak

• Cleavage and fracture

• Interaction with light

• Reaction with Acid and Water

Color • The color of the mineral helps you with

identification, but sometimes, the same mineral have different colors

LusterLuster • It is the way a mineral reflects light.

• Either metallicmetallic or nonmetallicnonmetallic

Light Interaction - Put the Light Interaction - Put the mineral on top of your book. If it mineral on top of your book. If it

is: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.

StreakStreak

• 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.

HardnessHardness

• A measure of how easily a mineral can be scratched by another mineral or other materilas

• For this test you use the Mohr’s Scale in the back of your handout

Ex of a Mohs ScaleMohs Hardness Scale

MineralTalc

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

Cleavage/ Fracture - the way a Cleavage/ Fracture - the way a mineral breaksmineral breaks

• Minerals that break along smooth, flat surfaces have cleavage.

• Minerals that breaks uneven, rough, or jagged surfaces have fracture.

Reaction with Acid

• Some minerals will fizz in contact with acids

• Others can dissolve in contact with water

• Also these properties will help identify a mineral