Mineral identification

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Slide 1

Section-2 Mineral Identification pg.68

Slide 2

What you’ll learn

Describe physical properties used to identify minerals.

Identify minerals using physical properties such as hardness and streak.

Slide 3

Physical Properties

Mineral appearance

Hardness

Luster

Specific gravity

Streak

Cleavage and fracture

Slide 4

Mineral appearance

How it looks like

What color is it?

Which one of the following is gold? Identify by appearance.

Slide 5

Hardness

A measure of how easily a mineral can be scratched

Slide 6

Properties of Minerals

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 scratch all other substances.

Testing Method

Slide 7

Luster

The way a mineral reflects a light luster.

Either metallic or nonmetallic

Slide 8

Specific Gravity

The specific gravity of a mineral is the ration of its weight compared with the weight of an equal volume of water.

Gold has specific gravity of 19

It means gold is 19 times heavier than water.

Slide 9

Specific gravity

Slide 10

Streak

When a mineral is rubbed across a piece of porcelain tile a streak of powdered mineral is left behind.

Slide 11

Cleavage

Cleavage is the way that mineral breaks.

Minerals that break along smooth, flat surfaces have cleavage.

Mica has cleavage