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Geology. Mineral (definition) naturally occurring, inorganic solid with a specific chemical composition a definite crystalline structure - PowerPoint PPT Presentation
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GeologyMineral (definition)1. naturally occurring, 2. inorganic solid 3. with a specific chemical composition 4. a definite crystalline structure
Minerals can form from the cooling of magma which is the molten material found beneath Earth’s surface as magma rises closer to the surface the molten compounds no longer move freely and they begin to interact chemically to form minerals
Geology Minerals form by combining elements
together to create compounds. Each compound is unique and has specific properties that separate it from other compounds
Minerals are like rocks because all rocks are made of minerals
Mineral Properties Streak is easily determined by rubbing
the mineral across an unglazed porcelain plate
Mineral Properties Streak is used to distinguish pyrite from
gold
Mineral Properties Luster is the way a mineral reflects light
from its surface and is caused by differences in mineral chemical compositions
Mineral Properties Either metallic or nonmetallic (dull,
pearly, waxy, silky)
Mineral Properties Texture describes how a mineral feels to
the touch Rough, smooth, ragged, greasy, soapy,
glassy
Mineral Properties Hardness is a measure of how easily a
mineral can be scratched and is determined by the arrangement of it’s atoms.
Mineral Properties The Mohs hardness scale is used to
compare a sample to the hardness of ten known minerals
Mineral Properties Cleavage determines whether a mineral
will split easily and evenly along one or more flat planes
Mineral Properties Mica has perfect cleavage in one
direction
Halite has cubic cleavage (3 planes)
Mineral Properties Fracture means the mineral is tightly
bonded and breaks with rough or jagged edges Quartz has fracture
Mineral Properties Specific Gravity compares the weight of
the mineral to an equal volume of water at 4 degrees C
Mineral Properties Special Properties such as light reflection
and reactions to acids are also useful tools
Mineral Properties Calcite fizzles when in contact with HCl
Mineral Properties Calcite also can cause double images
Mineral Properties Magnetite will attract iron
Mineral Properties Sulfur produces a rotten egg odor
Geology Small crystals
means the magma cooled rapidly
Large crystals means the magma cooled more slowly
Geology Silicates are the most abundant group
(96%) containing the two most abundant elements in the crust Silicon (Si) and Oxygen (O)
Geology Quartz and Feldspar are the most
abundant minerals found in Earth’s crust
Geology Carbonates are minerals composed of
one or more metallic elements with the carbonate compound CO3 ( 1 atom of carbon and 3 atoms off oxygen)
Geology Carbonates are the primary minerals in
rocks such as limestone, coquina, and marble
Limestone Coquina Marble
Uses for Earth Materials Nearly every single thing we use today
comes from Earth directly or indirectly. The following is a list of minerals and ores
Uses for Earth Materials Name of mineral/ore Use(s)Quartz (mineral) Glass, watches
Uses for Earth MaterialsFeldspar (mineral) Toothpaste
Uses for Earth Materials Calcite (mineral) Neutralizing
acids
Uses for Earth MaterialsMica (mineral) Lampshades, insulation, makeup
Uses for Earth MaterialsPyrite (ore) Iron
Uses for Earth Materials Talc Baby powder
Uses for Earth Materials Bauxite Aluminum
Virginia’s Important Resources Coal Energy
Virginia’s Important Resources Gravel/stone (all) Road
Construction
Virginia’s Important Resources Limestone Concrete
Virginia’s Important Resources Granite Building materials
Virginia’s Important Resources silica electronics
Virginia’s Important Resources zirconium & titanium advanced
metallurgy
What are Rocks? A rock is a naturally
occurring solid mixture of one or more minerals, or organic matter
Rocks are classified by how they are formed, their composition, and texture
Rocks change over time through the rock cycle
Igneous Rocks Igneous rock begins as magma. Magma can form:
When rock is heated When pressure is released When rock changes composition
Magma freezes between 700 °C and 1,250 °C
Magma is a mixture of many minerals
http://www.fi.edu/fellows/payton/rocks/create/igneous.htm
Igneous Rocks Felsic: light colored rocks that are rich in
elements such as aluminum, potassium, silicon, and sodium
Mafic: dark colored rocks that are rich in calcium, iron, and magnesium, poor in silicon
Coarse-grained: takes longer to cool, giving mineral crystals more time to grow
Fine-grained: cools quickly with little to no crystals
Igneous Rocks
Felsic
Mafic
Coarse-Grained
Fine-Grained
Granite
Gabbro Basalt
Rhyolite
Igneous Rocks Intrusive Igneous Rocks:
magma pushes into surrounding rock below the Earth’s surface
Extrusive Rocks: forms when magma erupts onto the Earth’s surface (lava), cools quickly with very small or no crystals formed
http://www.windows.ucar.edu/tour/link=/earth/geology/ig_intrusive.html&edu=high&fr=t
Igneous Rocks
Obsidian
What is Obsidian?
Obsidian is a dark-colored volcanic glass that forms from the very rapid cooling of molten rock material. It cools so rapidly that crystals do not form.
Obsidian is a dark-colored volcanic glass that forms from the very rapid cooling of molten rock material. It cools so rapidly that crystals do not form.
Is this rock Felsic or Mafic?
Is it fine-grained or coarse-grained?
Is this rock Intrusive or Extrusive?
Mafic, fine grained, extrusive
Sedimentary Rocks
http://www.fi.edu/fellows/payton/rocks/create/sediment.htm
Sedimentary rock is formed by erosion
Sediments are moved from one place to another
Sediments are deposited in layers, with the older ones on the bottom
The layers become compacted and cemented together
Sedimentary Rock Sedimentary Rocks are formed at or
near the Earth’s surface
No heat and pressure involved
Strata – layers of rock
Stratification – the process in which sedimentary rocks are arranged in layers
Sedimentary RockClastic – made of fragments of rock cemented together with calcite or quartzBreccia is a term most
often used for clastic sedimentary rocks that are composed of large angular fragments (over two millimeters in diameter).
The spaces between the large angular fragments can be filled with a matrix of smaller particles or a mineral cement that binds the rock together.
Sedimentary RockChemical sedimentary – minerals crystallize out of solution to become rockRock Salt is a chemical
sedimentary rock that forms from the evaporation of ocean or saline lake waters. It is also known by the mineral name "halite". It is rarely found at Earth's surface, except in areas of very arid climate. It is often mined for use in the chemical industry or for use as a winter highway treatment. Some halite is processed for use as a seasoning for food. The specimen shown above is about two inches (five centimeters) across.
Sedimentary Rock
Limestone is a sedimentary rock composed primarily of calcium carbonate (CaCO3) in the form of the mineral calcite. It most commonly forms in clear, warm, shallow marine waters.
It is usually an organic sedimentary rock that forms from the accumulation of shell, coral, algal and fecal debris.
Organic sedimentary – remains of plants and animals
Sedimentary RockOrganic sedimentary – remains of plants and animals
Coal is an organic sedimentary rock that forms from the accumulation and preservation of plant materials, usually in a swamp environment.
Coal is a combustible rock and along with oil and natural gas it is one of the three most important fossil fuels.
Metamorphic Rock
http://www.fi.edu/fellows/payton/rocks/create/metamorph.htm
Meaning to change shape
Changes with temperature and pressure, but remains solid
Usually takes place deep in the Earth
Metamorphic Rocks Contact Metamorphism – heated by nearby
magma Increased temperature changes the
composition of the rock, minerals are changed into new minerals
Hornfels is a fine-grained non-foliated metamorphic rock produced by contact metamorphism http://www.windows.ucar.edu/tour/link=/earth/geology/meta_contact.html&ed
u=h igh&fr=t
Metamorphic Rocks Regional Metamorphism –
pressure builds up in rocks that is deep within the Earth
Large pieces of the Earth’s crust collide and the rock is deformed and chemically changed by heat and pressure
http://www.windows.ucar.edu/tour/link=/earth/geology/meta_regional.html&edu=high&fr=t
Metamorphic Rock Foliated - contain aligned grains of flat
mineralsGneiss is foliated metamorphic rock that has a banded appearance and is made up of granular mineral grains.
It typically contains abundant quartz or feldspar minerals.
Metamorphic Rock Non-Foliated – mineral grains are not
arranged in plains or bands
Marble is a non-foliated metamorphic rock that is produced from the metamorphism of limestone.
It is composed primarily of calcium carbonate.
Metamorphic Rock Determine if the following rock samples
are foliated or non-foliated:
Amphibolite Quartzite Phyllite
Foliated