definition of a mineral 2.2 minerals 1. naturally occurring 2. solid substance 3. orderly...
TRANSCRIPT
Definition of a Mineral
2.2 Minerals
1. Naturally occurring
2. Solid substance
3. Orderly crystalline structure
4. Definite chemical composition
5. Generally considered inorganic
How Minerals Form
2.2 Minerals
1. Crystallization from magma
2. Precipitation
3. Pressure and temperature
4. Hydrothermal solutions
Mineral Groups Can be classified based on their
composition
2.2 Minerals
1. Silicates• Silicon and oxygen combine to form a structure
called the silicon-oxygen tetrahedron. This provides the framework of every silicate mineral.
• Ex. Quartz, Feldspar, Olivine, Mica
The Silicon-Oxygen Tetrahedron
Mineral Groups
2.2 Minerals
2. Carbonates• Contain the elements carbon, oxygen, and one
or more other metallic elements• EX. Calcite, Dolomite
3. Oxides• Contain oxygen and one or more other
elements, which are usually metals• Ex. Corundum, Hematite
2.2 Minerals
4. Sulfates and Sulfides• Contain the element sulfur• Sulfates also contain Oxygen• Ex. Galena, Pyrite, Sphalerite
5. Halides• Contain a halogen ion plus one or more other
elements• Ex. Fluorite, Halite
6. Native elements• Exist in relatively pure form• Ex. Gold, Diamond, Lead, Silver
Color
2.3 Properties of Minerals
Small amounts of different elements can give the same mineral different colors.
Streak is the color of a mineral in its powdered form.
Streak
Luster
2.3 Properties of Minerals
Luster is used to describe how light is reflected from the surface of a mineral.
Pyrite (Fool’s Gold)
Think “shiny” and “dull”
Crystal Form
2.3 Properties of Minerals
Crystal form is the visible expression of a mineral’s internal arrangement of atoms.
Hardness
2.3 Properties of Minerals
Hardness is a measure of the resistance of a mineral to being scratched.
Mohs scale consists of 10 minerals arranged from 10 (hardest) to 1 (softest).
Cleavage
2.3 Properties of Minerals
Cleavage is the tendency of a mineral to cleave, or break, along flat, even surfaces.
Fracture
2.3 Properties of Minerals
Fracture—the uneven breakage of a mineral
Density
2.3 Properties of Minerals
Density = Mass / Volume
Distinctive Properties of Mineralsfluorescence, optical properties, radioactivity, magnetism, taste, and reactions to chemicals.
To be classified as a mineral a substance must
meet all of the following characteristics: • Inorganic (not formed by life processes)• Formed in nature (synthetic substances are not
considered minerals)• Solid• Atoms have the same crystalline pattern
(crystal shape is visible, but few are perfect).• Identifiable chemical composition (has the
same kinds of atoms arranged throughout in the same way and in the same proportions).
In summary, a mineral is a naturally occurring, inorganic solid that has a definite chemical composition and crystal structure.
Just Read !
How common are minerals?How common are minerals?
• There are about 3500 known minerals
• The 20 most common minerals make up 95% of the Earth’s crust
• ALL rocks are composed of minerals
Aquamarine
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MINERAL USE
copper electrical wiring, coins
gold computer circuitry , UV protection for astronauts
magnetite natural magnet
halite table salt
fluorite toothpaste
galena car batteries, iron extraction
molybdenite steel and soil additive
sulfur matches
zeolite water softener
diamond drills
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Rocks
3.1 The Rock Cycle
Rocks are any solid mass of mineral
3 Types of Rocks
1. Igneous rock - formed by the crystallization of molten magma.
Rocks
3.1 The Rock Cycle
Types of Rocks2. Sedimentary rock - formed from the
weathered products of preexisting rocks that have been compacted, and cemented.
3. Metamorphic rock - formed by the alteration of pre-existing rock deep within Earth by heat and pressure
The Rock Cycle
3.1 The Rock Cycle
Rock Cycle shows the interrelationships among the three rock types
Energy That Drives the Rock Cycle
1. Heat from the Earth’s interior
2. Energy from the sun
- powers weathering processes
Formation of Igneous Rocks
3.2 Igneous Rocks
1. Intrusive igneous rocks are formed when magma hardens beneath Earth’s surface. Cools very slowly!Ex. Granite *larger crystals
2. Extrusive igneous rocks are formed when lava hardens. Cools quickly! Ex. Obsidian *smaller crystals
Classification of Igneous Rocks
3.2 Igneous Rocks
1. Texture
Classified based on composition & texture.
• Coarse-grained texture is caused by slow cooling resulting in larger crystals.-intrusive
• Fine-grained texture is caused by rapid cooling resulting in smaller, interconnected mineral grains.- extrusive
Classification of Igneous Rocks
Formation of Sedimentary Rocks
3.3 Sedimentary Rocks
• Erosion involves the weathering and the removal of rock.
• Deposition occurs when an agent of erosion—water, wind, ice, or gravity—loses energy and drops sediments.
Formation of Sedimentary Rocks
3.3 Sedimentary Rocks
• Compaction is a process that squeezes, or compacts, sediments.
• Cementation takes place when dissolved minerals are deposited in the tiny spaces among the sediments. (holds the material together like glue)
Classification of Sedimentary Rocks
3.3 Sedimentary Rocks
1. Clastic sedimentary rocks are composed of weathered bits of rocks and minerals.
• Classified by particle size
- Shale, Sandstone, Conglomerate
• Common rocks include
Classification of Sedimentary Rocks
3.3 Sedimentary Rocks
2. Chemical sedimentary rocks form when dissolved substances precipitate, or separate, from water. • Common rocks include
-Limestone, Coal
3.3 Sedimentary Rocks
Features of sedimentary rocks are clues to how and where the rocks are formed
Formation of Metamorphic Rocks
3.4 Metamorphic Rocks
Metamorphism means “to change form.”
Conditions for formation are found a few kilometers below the Earth’s surface and extend into the upper mantle.
Most metamorphic changes occur at elevated temperatures and pressures.
Formation of Metamorphic Rocks
3.4 Metamorphic Rocks
Contact metamorphism occurs when magma moves into rock.
Regional metamorphism results in large-scale
deformation and high-grade metamorphism.
Agents of Metamorphism
3.4 Metamorphic Rocks
Heat
Pressure
• Provides the energy needed to drive chemical reactions
• Causes a more compact rock with greater density
Classification of Metamorphic Rocks
3.4 Metamorphic Rocks
1. Foliated Metamorphic Rock
2. Nonfoliated Metamorphic Rock
Two main categories
• Has a banded or layered appearance• Ex. Gneiss
• Does not have a banded texture• Ex. Marble
Classification of Metamorphic Rocks
This process can take billions of years!
Rock Cycle Song(Sing to the tune of "Row, Row, Row Your Boat")
SEDIMENTARY rockHas been formed in layersOften found near water sourcesWith fossils from decayers
Then there's IGNEOUS rockHere since Earth was bornMolten Lava, cooled and hardenedThat's how it is formed
These two types of rocksCan also be transformedWith pressure, heat and chemicalsMETAMORPHIC they'll become.( Don't forget to sing this as a "Round"; after all, it is the Rock "Cycle"! )