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The study of the composition, structure, appearance, stability occurrence, and associations of
minerals.
Mineralogy
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A naturally occurring, inorganic, homogeneous solid with a specific chemical composition
and crystalline structure.
Mineral
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The smallest unit
of an element retaining the physical and chemical properties of that element.
Atom
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Center of an atom containing protons and neutrons.
Nucleus
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Negatively charged
(-) particles which revolve around the nucleus
Electron
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The number of protons contained in the nucleus
Atoms of the same element always have the
same number of protons.
Atomic number
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The
sum of the protons and neutrons
Atomic mass
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Atoms with different numbers of neutrons.
Isotopes
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nucleus spontaneously loses energy by emitting radiation and changing from one element (parent) into
another element (daughter).
Radioactive decay
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Chemical Reactions
When two elements combine together, they produce chemical compounds. Chemical compounds share electrons.
- A. Ionic bonds – held together by opposite charges
- B. Covalent bonds – electrons are shared by multiple atoms
- C. Metallic bonds – lose electrons easily.
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Atoms of a gas or liquid join in certain chemical proportions and crystalline arrangement.
Crystallization
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When do minerals form?
- 1.Fall in temperature of a liquid below its freezing point
- Crystallization of ice forms below 32 degrees
2.Evaporation
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the most abundant minerals in the Earth’s crust. Composed of Oxygen (O) and Silicon (Si), the two most abundant elements in the crust.
Silicates
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8 classes of minerals
Carbonates – carbon ion surrounded by 3 oxygen ions, arranged in sheets
Example: calcite, dolomite
Oxides
– oxygen is bonded to metallic ions
Example: hematite
Sulfides
– sulfide ion (S2-) is bonded to metallic ions E
Example: pyrite
Sulfates
– sulfur atom is bonded to 4 oxygen ions
Example: gypsum
Native
Elements – pure elements Example: copper, gold
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measure of the ability to scratch or be scratched
Hardness
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Tendency of a mineral to break along flat planar surfaces.
Cleavage
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3. Luster – how the surface of the mineral reflects light
4. Color – appearance of a mineral in light
- streak: color of powdered mineral
5. Specific gravity – weight of a mineral divided by the weight of an equal volume of pure water
at 4 degrees Celsius.
6. Crystal habit – the shape individual crystals grow.
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A naturally occurring solid aggregate of minerals or non-mineral solid matter
Rocks
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-mineralogy: minerals which comprise the rock
- texture: describes the size and shapes
of the minerals and how they are put together.
a. coarse – individual grains can easily
be seen
b. fine – individual
grains are not visible
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all rocks formed by solidification of molten rock
Igneous rocks
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All rocks formed as the burial products of layers of sediments. Most formed under water.
Sedimentary rocks
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All rocks formed by the transformation of existing rocks through temperature and /or high pressure.
Metamorphic rocks
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Types of igneous rocks
A.Intrusive – magma
(molten rock) moved into other rock underground.
- slow cooling, allows individual
crystals to grow quite large.
B. Extrusive rocks – magma reaches the surface of the earth through eruption from
volcano.
- very rapid cooling, individual crystals
are very tiny. Glassy, fine grained textures.
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Sedimentary Rocks
-Formed from
sediments: layers of loose particles created from weathering and erosion.
Weathering– chemical and physical processes that break up and decay rocks into smaller
rocks or fragments.
Erosion– a set of processes that loosen soil and rock and move them to a place of
deposition.
Siliciclastic sediments – physically deposited particles laid down by
running water, wind, and ice forming layers of sand, silt, and gravel.
Chemical and biochemical sediments – new chemical substances formed by precipitation.
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process which converts sediments into rocks
Lithification
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Metamorphic Rocks
Result when high temperatures and pressure are applied to igneous and sedimentary
rocks. The existing rocks are changed into metamorphic rocks.
Regional metamorphism – extends over large regions where two tectonic plates are
colliding together.
Contact metamorphism – occurs in a very small area where igneous or sedimentary rocks
are in direct contact with high heat or pressure.
Foliation – wavy or flat planes formed when a rock undergoes metamorphism.
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Ore – large enough quantities of mineral deposits from which valuable metals can be
recovered profitably.
Hydrothermal solutions – when magma is moving through rock, it comes in contact with groundwater. The water can carry off important minerals in a solution into areas the magma does not reach.
Veins– the joints and fractures in rock where economically important minerals are deposited by hydrothermal solutions.
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