WHAT IS A MINERAL?- A NATURALLY OCCURRING SOLID THAT CAN FORM BY

INORGANIC PROCESSES AND THAT HAS A CRYSTAL STRUCTURE AND A DEFINITE CHEMICAL COMPOSITION.

- REQUIREMENTS:

- 1. Naturally occurring: formed by natural processes- 2. Solid: have a definite volume and shape- 3. Crystal structure: particles line up in a repeating

pattern (flat sides that meet a sharp edges and corners)

- 4. Forms by Inorganic processes: must form from materials that were NOT living things

- 5. Definite Chemical Composition: always contains certain elements in definite proportions

Properties of Minerals

How Are Minerals Identified?

Each mineral has characteristic properties that can be used to identify it. Color Streak: the color of its powder (can be different from its

mineral color) Luster: how light is reflected from a mineral’s surface Hardness: Mohs hardness scale used to rank the hardness

of minerals (1-10) A mineral can scratch any mineral softer than itself, but cannot scratch a mineral harder than itself.

Density: each mineral has a specific density. - Density = Mass/volume

Crystal Structure: all the crystals of a mineral have the same crystal structure

Cleavage and Fracture: A mineral that splits easily along flat surfaces has the property called cleavage. A mineral that breaks apart in an irregular way has the property fracture.

How Do Minerals Form?

Geode- A crack or hollow forms in a rock Water containing dissolved minerals seeps in Crystalization slowly occurs Geode is complete

Other Ways…

Organic Minerals: Ex, ocean animals such as clams and corals produce shells and skeletons made out the mineral calcite.

Minerals from Solutions: When elements and compounds that are dissolved in water leave a solution, crystallization occurs.

Minerals from Magma and Lava: Minerals form as hot magma cools inside the crust, or as lava hardens on the surface. When liquids cool to solid state, they form crystals.

Where Mineral Resources Are Found: Earth’s crust is made up of common rock-forming minerals.

Classifying Rocks!

How Do Geologists Classify Rocks? 1. Mineral Composition and Color 2. Texture

- Grain Size- Grain Shape- Grain Pattern

3. Origin:- Igneous Rock – forms from the cooling of magma or lava- Sedimentary Rock – forms when small particles of rocks

or the remains of plants and animals are pressed and cemented together

- Metamorphic Rock – forms when a rock is changed by heat or pressure, or by chemical reactions.

- See p225

The Rock Cycle

Forces deep inside Earth and at the surface produce a slow cycle that builds, destroys, and changes the rocks in the crust. The rock cycle is a series of processes that slowly change rocks from one kind to another.

See p228