Notes on 32-34 and 35-39

Defining Minerals

A mineral is a naturally occurring solid that can form by inorganic processes and that has a crystal structure and a definite chemical composition.

Minerals, Compounds, and Elements

Almost all minerals are compounds.

In a compound, two or more elements are combined so that the elements no longer have distinct properties.

Sulfur is bright yellow, Mercury is silvery liquid at room temperature. But cinnabar has solid, shiny, red crystal.

Different minerals have a different combination of elements. For an example, a crystal of quartz has no atom of silicon.

What is a mineral?

Solid

Naturally occurring

Inorganic

Fixed composition

Crystal form

Some examples:

Minerals:
Gold
Topaz
Quartz
Talc
*Ice burg*
Diamonds

Non-Minerals:
Wood: Once living
Fossils: Once living
Bone: Living material
Granite: Intrusive igneous rock
Pearls: Made by oysters
Coal: Sedimentary rock
Rock salt: Sedimentary rock

Questions that you should ask yourself?

• Is it non-living material?
• Is it a solid?
• Is it formed in nature?
• Does it have a crystalline structure?

The definition of a mineral:
A mineral is a naturally formed inorganic solid that has a definite crystalline structure.

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Assess your understanding;

1. All minerals are formed from inorganic processes.

2. Every mineral needs to be able to form from materials that are non living.

3. Amber is not a mineral because it is made by a living thing just like coal is.

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How are Minerals Identified?

Each mineral has characteristics properties that can be used to identify it.

Color: What the color of the mineral is.

Streak: The streak of a mineral is the color of its powder.

Luster: Luster is the term used to describe how light is reflected from a mineral’s surface.

Hardness

Topaz: It can scratch quartz but not corundum. Gypsum: A fingernail can easily scratch it. Apatite: A steel knife can scratch it. Diamond: Extremely hard, it can scratch all known common Minerals. Quartz: It can scratch feldspar but not topaz.

Crystal Structure:

The atoms that make up a mineral line up in a regular pattern. This pattern repeats over and over. The repeating pattern of a mineral’s atoms forms a mineral’s crystal structure.

Cleavage and Fracture

A mineral that splits easily along flat surface has the property called cleavage.

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Fracture describes how a mineral looks when it breaks apart in an irregular way.

SPECIAL PROPERTIES:

Some minerals can be identified by special physical properties. Calcite bends light to produce double images. Other minerals conduct electricity, glow when placed under ultraviolet, or are magnetic.

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Assess your understanding;

1. Geologists identify the minerals by examining how the mineral brakes apart(cleavage and fracture) and by the color, streak, luster, density, crystal structure, and hardness.

2. Lodestone is magnetic, you could find out if a mineral is magnetic by putting metal in front of it to see if they attract to each other.