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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!