Geology Ch. 4 ( Minerals and Rocks) – Flashcards
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Mineralology
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the branch of geology that studies the composition, structure, appearance, stability, occurrence, and associations of minerals.
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Mineral
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naturally occurring, solid crystalline substance, usually inorganic, with a specific chemical composition.
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Atom
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the smallest unit of an element that retains the physical and chemical properties of that element.
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Isotopes
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atoms of the same element with different numbers of neutrons.
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Chemical reactions
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interactions of the atoms of two or more chemical elements in certain fixed proportions that produce chemical compounds.
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Ion
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an atom or a group of atoms that has an electrical charge, either positive of negative, because of the loss or gain of one or more electrons.
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Chemical bonds
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the electron attraction between negatively charged electrons and positively charged protons.
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Crystallization
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the atoms of a gas or liquid come together in the proper chemical proportions and crystalline arrangement to form a solid substance.
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Crystals
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orderly three-dimensional arrays of atoms in which the basic arrangement is repeated in all directions.
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Magma
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hot, molten liquid rock.
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Polymorphs
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alternative structures formed from a single chemical compound.
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Density
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mass per unit volume, expressed in grams per cubic centimeter, g/cm^3.
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Hardness
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a measure of the ease with which the surface of a mineral can be scratched.
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Mohs scale of hardness
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is based on the ability of one mineral to scratch another.
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Cleavage
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the tendency of a crystal to split along planar surfaces (also used to describe the geometric pattern produced by such breakage).
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Fracture
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the tendency of a crystal to break along irregular surfaces other than cleavage planes.
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Luster
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the way the surface of a mineral reflects light gives it this characteristic.
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Color
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imparted by light, either transmitted trough or reflected by crystals or irregular masses of the mineral or a streak of mineral powder.
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Streak
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refers to the color of the fine deposit of mineral powder left on an abrasive surface, such as a tile of unglazed porcelain, when a mineral is scraped across it.
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Specific gravity
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the weight of a mineral divided by the weight of an equal volume of pure water at 4 degrees Celsius ( a standard measure of density).
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Crystal habit
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the shape in which individual crystals or aggregates of crystals grow.
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Rock
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a naturally occurring solid aggregate of minerals or, in some cases, nonmineral solid matter.
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Texture
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describes the sizes and shapes or a rock's mineral crystals or grains and the way they are put together.
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Igneous rocks
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a type of rock that is formed by the solidification of molten rock.
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Sedimentary rocks
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these rocks are formed as the burial products of layers of sediments ( such as sand, mud, or calcium carbonate shells), whether they were laid down on land or under the sea.
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Metamorphic rocks
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all rocks formed by the transformation of preexisting rocks under the influence of high pressure and temperature.
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Intrusive igneous rocks
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rocks that crystallize when magma intrudes into unmelted rock masses deep in Earth's crust.
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Extrusive igneous rocks
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rocks that form from magmas that erupt at the surface through volcanoes and cool rapidly.
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Sediments
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the precursors of sedimentary rocks that are found on Earth's surface as layers of loose particles, such as sand, silt, and the shells of organisms.
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Weathering
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refers to all the chemical and physical processes that break up and decay rocks into fragments and dissolved substances of various sizes.
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Erosion
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the set of processes that loosen soil and rock and move them downhill or downstream to the spot where they are deposited as layers of sediment.
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Lithification
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the process that converts sediments into solid rock
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Bedding
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the formation or parallel layers of sediment as particles settle to the bottom of a water body or on a land surface.
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Regional metamorphism
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this occurs where high pressures and temperatures extend over large regions, as happens where plates collide.
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Contact metamorphism
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high temperatures are restricted to smaller areas, as in the rocks near an in contact with a magmatic intusion.
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Foliation
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wavy of flat planes produced when the rock was structurally deformed into folds.
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Rock cycle
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explains how each type of rock is converted into one of the other two types.
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Ores
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rich deposits of minerals fro which valuable metals can be recovered profitably.
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Hydrothermal solutions
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very large ore deposits can be formed in such a tectonic setting when hot water solutions are formed around bodies of molten rock.
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Veins
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tabular ( sheet-like) deposits of precipitated minerals in the fractures and joints.
