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116 Cards in this Set
- Front
- Back
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Most earthquakes are caused by
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rocks breaking suddenly from geologic forces
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3 types of seismic waves
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Primary, secondary and surface
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Amplitude of the largest secondary wave
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earthquake magnitude
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Elastic rebound theory
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theory that explains the buildup of energy (bending) in the rocks that are under stress and the subsequent release of that energy through faulting (rupture)
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Cause of 1964 Alaskan Earthquake
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subduction of Pacific Plate under Alaska
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Seismic waves are generated when
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stored energy in a rock is released due to faulting
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Distance between two wave crests
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wavelength
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Seismology is the study of
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earthquakes
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Most deaths in the Alaskan Earthquake caused by
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a tsunami
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1906 San Francisco equake caused by
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movement along a transform fault
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Point of energy release that causes equake
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focus
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Seismographs rely on
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inertia to detection motion on surface
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1906 and 1989 San Fran equake had different magnitude because
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a larger segment of the fault ruptured in 1906
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Location of the epicenter is determined by
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drawing circles around three seismic stations, the radius of the circles correspond to the different arrival times of the p and s waves
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Surface waves
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Have slower velocities than P&S waves, Travel along the surface of the earth, Are the last wave to be detected, Cause the most damage
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Richter scale
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measure the amount of energy released during an equake
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San Andreas fault
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characterized as a fault that has locked and creeping parts
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The location of equakes world wide are controlled by
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plate boundaries
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Why are there few earthquakes on the East Coast, but many on the West Coast?
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The East Coast has a passive margin and the West Coast has transform and convergent faults
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Liquefaction
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the process of transforming granular material from solid to liquid
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Ground oscillation
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a type of liquefaction that causes fissures to open and close
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A tsunami is typically formed by
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rapid displacement of large areas of the sea floor
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Tsunami has the following characteristics
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fast speed, long wavelength and long period
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Most of the damage of the 1906 San Francisco equake was caused by
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fire
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What is not true about the spatial distribution of equakes
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10% occur in mantle, TRUE – 15% in Med. Asiatic belt, 80% in Circum pacific belt, 5% mid Atlantic ridges and plates
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Most of the damage in the 1989 S.F. equake was caused by
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the collapse of structures
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Double-decker highway in S.F. collapsed only in one location because
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that location was underlain by loose material that shook by solid bedrock
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Equakes in Washington and Oregon are caused by
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Oceanic-continental crustal convergence
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Cause of the Earth’s magnetic field
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circulation of the liquid outer core generates an electrical field
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Refraction of seismic waves occurs when
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seismic waves travel through material with a different density
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Reflection of seismic waves occur when
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seismic waves bounce off of layers with a different density
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Liquid nature of the outer core was determined by
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large S wave shadow zone opposite the equake location
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The mantle has seismic velocities that correspond to a rock type called
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Periodite
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Moho or M-discontinuity
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a seismic discontinuity that marks that boundary between crust and mantle
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Composition of the Earth’s core
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iron and a little nickel
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Composition of the Earth’s core is determined by
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seismic wave velocity
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Speed of seismic waves
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increase upon encountering denser rocks
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Seismic waves travel in a curved path as they travel through the Earth because
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refract as they pass through different densities
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Moho was discovered when
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two distinct sets of P&S waves were detected for a single seismic event
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Asthenosphere identified by
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a low velocity zone in the mantle
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Which of the following features characterize river systems
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stream gradient decreases, discharge increases, competence increases down stream
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Glaciers
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contain the largest amount of fresh water
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The top of the saturated zone is called the
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water table
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The shape of the water table
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mimics the land surface
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Recharge zone
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the place where precipitation enters the aquifer
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The direction of ground water flow is controlled by
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pressure surface (to lower numbers)
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Ground water flows
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down potential
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Hydrologic cycle
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evaporation, precipitation, ground water back to ocean, runoff
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Rock that inhibits the flow of water
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aquitard
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Nile
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longest river in the world
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The height that water will rise in a well drilled into a confined aquifer is called
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potential surface
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The land around the San. Fran Bay area experiences more shaking than surrounding areas because
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the land around the bay area is composed of poorly consolidated material
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Tributaries
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V downstream
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Rovers flow after rain has fallen because
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ground water discharges into stream beds
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Continued pumping of a water well results in
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a cone of depression
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Karst topography forms when
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solution cavities create caves that cause the land surface to become bumpy and irregular
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Barton Springs is often closed because
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ground water transports pollution into the swimming hole
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Ground water flows to
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lower #’s (Florida graph)
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Seismology
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the study of earthquakes
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Seismograph
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detects vibrations and shaking
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Seismogram
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reading by the seismograph
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Wavelength
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distance from wave crest to wave crest
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Equake focus
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point of energy release
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Not a characteristic of a P wave
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motion of wave is perpendicular to direction, TRUE – first detected, pulse of compression and expansion, changes in volume and density
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As the time interval increases between P&S waves
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the farther the epicenter is
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Surface waves
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same as body waves
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Epicenter located by
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using 3 seismic stations
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the big bang theory
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-all material in the universe was located at one point
-13.7 billion yrs ago the material moved outward from that location |
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why do scientists think the universe is expanding?
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- everything is moving away from everything else
-based on red shift of light observed in telescopes -red shift – Doppler effect |
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red shift
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when light is moving away the light gets stretched out and pitch falls
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how old is the universe?
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Estimate is 13.7 billion years
Determined by time required to move everything back together |
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First material to form were
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hydrogen and helium. These are still the two most abundant elements in the universe
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Where did other elements come from?
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Heavier elements are formed in stars. Through the process of fusion- combining elements under high pressure and temp. Fusion gives off a huge amount of heat.
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nova
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exploding star, origin of our solar system
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rotating nebula
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rotating nebula- cloud of gas and dust. gravitational attractions formed the sun and planets.
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most nebula is made of
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hydrogen and helium
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impact energy
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bolide (meteor)
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gravitational energy
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gravity is the attraction between solid bodies.
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radioactive decay
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the spontaneous destruction of unstable atoms
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3 types of radioactive emissions
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-alpha particles (2 protons, 2 neutrons)
-beta particles (high energy electron) -gamma rays (high energy elctro magnetic energy) |
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sun
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fusion of hydrogen releases enormous amounts of energy,
causes volcanoes and earthquakes |
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mineral
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naturally occurring inorganic solids (no organic compounds. Solid)
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Crystalline
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orderly and repetitive atomic arrangement (repeating symmetrical arrangement)
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Is glass a mineral?
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No
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Is wood a mineral?
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no
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Is mercury a mineral?
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No. It is a liquid.
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Is ice a mineral?
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Yes.
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atoms
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the smallest particle that retain the character of an element
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nucleus
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proton + neutron
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extranuclear
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electron
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number that defines the element
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proton
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8 most abundant elements in the earths crust
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oxygen, silicon, aluminum, iron, magnesium, calcium, sodium, potassium
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State of matter is controlled by
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temperature and pressure- controls the arrangement of the atoms
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States of matter
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Gas, liquid, or solid
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crystal form
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arrangement of flat growth faces, a reflection of the internal arrangement of the atoms, reflected in the external shape
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Cleavage
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flat faces that occur when the mineral is broken, represents planes of weak atomic bonds
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Hardness
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a mineral’s resistance to scratching
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moh’s scale of hardness: softest & hardest
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talc & diamond
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color
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caused by tiny impurities
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streak
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the color of finely powdered mineral
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luster
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the way light reflects off of a mineral (metallic/ glassy)
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mineral origin
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atoms bond together to form a crystalline structure
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Two places minerals form and grow
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magmatic environment, aqueous environment
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gem
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a mineral which by cutting and polishing poses sufficient beauty to be used in jewelry, typically rare and durable
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Of the 3500 known minerals only __ are considered important gem minerals
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15
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largest producer of diamonds
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South Africa
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rock
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a lump or mass of consolidated mineral matter
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Igneous rocks
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formed by the solidification of magma
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metamorphic rocks
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form in the solid state in response to changes in the temperature and pressure
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Sedimentary rocks
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composed of fragments of pre-existing rocks
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Magma
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melted rock capable of penetrating through other rocks
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Glassy
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no distinct grains- rapid cooling
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Aphanitic
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fine grained- extrusive- quick cooling
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Phaneritic
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coarse grained- intrusive magma cooled slowly
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Batholiths
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huge masses of coarsely crystalline igneous rocks
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Stock
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a small batholith
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