Section 5.1 and 5.2 Minerals

Minerals: What are They? Composition and Formation

Minerals are essential:

• They are every manufactured product.

• They’re essential to good health (vitamins and minerals).

• Knowledge of minerals enables us to understand Earth’s processes.

What is a mineral?

Five characteristics that make a substance a mineral:

• _____________________• _____________________• _____________________• _____________________• _____________________

Occurs naturally

Solid

Definite chemical formula

Orderly (crystal) arrangement of atoms

Inorganic (never alive)

Top 8 elements in the Earth’s crust:

#1#2 ______________________#3 ______________________#4 ______________________#5 ______________________#6 ______________________#7 ______________________#8 ______________________

Oxygen 46.6%_Silicon 27.7%Aluminum 8.1%

Iron 5.0%

Calcium

Sodium

Potassium

Magnesium

Silicates

Most minerals are …a) Compounds?b) Elements?c) Mixtures?

Examples:Salt (NaCl)

calcite (CaCO3)

Sand (SO2)

Native minerals are composed of just one, single element.

• Examples:

1. ____________________ 2. ____________________ 3._____________________

Gold

Copper

Diamond *

* Is diamond an element on the Periodic Table??

The Rock

What is a ROCK by definition?

A group of one or more minerals

bound together

in varying quantities

Except…..

• Limestone, which is made of only ONE mineral:

calcite.

How Minerals Formpage 97

Magma Pressure Process Evaporation Process (Precipitation)(most)

How Minerals form (pg.97)

The Magma Process:

1. Molten (liquid) rock in a magma chamber at, near, or under earth’s surface, rises

2. The magma begins to cool and atoms, ions and molecules form various mineral compounds.

3. The molecules of the compounds mass together to form crystals.

The Pressure Process:

1. Rock is exposed to high pressures and temperatures, and the minerals begin to break down.

2. As pressure and temperature continue, the molecules RE-FORM into new minerals.

3. The minerals are elongated in shape due to the pressure.

The Evaporation Process:1. Ions (such as salt or calcium) are dissolved in water.

2. The water evaporates, and the ions form minerals such as halite and calcite.

• Examples: halite (NaCl salt)» limestone (calcite)

The kind of mineral that is formed depends on…

1. Which elements are present when it forms

2. The amount of an each element present.

* The same magma chamber can form different minerals.

crystal = regular, orderly arrangement of atomsFactors that determine crystal formation:

1. Time2. Space3. Temperature4. Pressure5. Concentration

Largest uncut diamond found in the Letseng Mine in southern Africa. A near-flawless white gem weighing nearly 500 carats. It was discovered on Sept. 8, 2008 It weighs 478 carats, with very few inclusions and of outstanding color and clarity.

1. TIME and mineral formation

The RATE at which the molten magma cools determines the crystal size.

• If the magma cools s-l-o-w-l-y then the crystals will….

* (example: granite)

be LARGE and well-formed

#44

• If the magma cools quickly, then the crystals will….

*example: obsidian cools instantly so it has no crystal structure, but a glass-like structure

be Small / microscopic / not well-formed

Classzone Internet Investigation ES0506

“How Do Crystals Grow?”

2. Space3. Temperature4. Pressure

http://www.classzone.com/books/earth_science/terc/content/investigations/es0506/

Answer #1-8 on a separate sheet of paper!