Mineralogy Test section Flashcards

Terms Definitions
polysynthetic twinning
layered twinns
dodecahedral (coordination)
12-fold coordination
Contact Twin Minerals  
Spinel, Quartz
reniform
having a kidney-shaped appearance
monomineralic
containing only one mineral
Twin Boundary
is a "composition plane"
Composition Plane  
an added mirror plane
phenocryst
the relatively large, conspicuous crystals in a porphyritic rock
pegmatite
an exceptionally coarse grained igneous rock; generally formed by crystallization of water-rich magmas
hornfels
a fine-grained metamorphic rock lacking foliation or lineation
lattice
a three-dimensional representation of the translational symmetry of a crystal structureq
detritus
broken-up material resulting from mechanical weathering
polymorphs
minerals that have identical compositions but different crystal structures; for example, calcite and aragonite are polymorphs
globular
appearing as spherical or hemispherical shapes made of radiating crystals (see also colloform)
gemstone
a gem of mineralogical origin
nesosilicates
silicate minerals characterized by individual SiO4 tetrahedra linked by bonding to common cations (see also island silicates and isolated tetrahedral silicates)
fool's gold
common name foor pyrite
granular
cojmposed of many small grains
Allochromatic
minerals with color where chromophore is impurity e.g. Al2O3 corundum
Residual Processes
Nature of Process:
Leaching from rocks of soluble elements leaving concentrations of insoluble elements in the remaining material
Typical Deposits:
Nickel laterites
Most bauxites
Kaolin deposits
contact metamorphism
metamorphism localized around an igneous rock body; primarily in response to heat and flowing fluids.
layer silicates
silicate minerals characterized by SiO4 tetrahedra joining to form sheets; includes micas and clays (see also sheet silcates and phyllosilicates)
network silicates
silicate minerals characterized by SiO4 tetrahedra joining to form three-dimensional networks ( see also tectosilicates and framework silicates)
greenschist (facies)
a medium-grade metamorpich facies characterizing conditions of about 300-500 C and 2-8 Kbar
x ray
electromagnetic wave with wavelength much shorter than visible light, on the order of 0.1 to 100A (see also x-radiation)
augen
lagrge lenticular mineral grains or mineral aggregates in a foliated metamorphic rock
phaneritic
having mineral grains visible without a microscope
monochromatic
a term describing radiation consisting of one wavelength
amphibolite (rock)
a metamorphic rock containing primarily hornblende and plagioclase
unmixing
the separation of an initially homogeneous solid, liquid, or gas phase into two or more of differnt compositions
Carbonate (radical)
the (CO3) 2- anionic group
Idiochromatic
mineral has chromophores as a major element (Fe,Mg)2 SiO4
Anisotropic Substances
Substance through which the properties of light vary depending on the crystallographic direction - multiple refractive indices
Includes all crystals except isometric minerals
Nucleation
the first stage of growth, which starts with the formation of a nucleus or seed.
Anisodesmic
is a crystal containing bonds with differing electrostatic valencies. All other crystals are known as isodesmic crystals (or isodemic) and examples include diamond and halite.
Twinning
Two seperate crystals sharing some of the same crystal lattice points
orthorhombic
of or related to the orthorhombic crystal system
fibrous (crystals)
having the appearance of being composed of fibers
porcelain
a special type of high-quality white ceramic
pisolitic
a term describing crystals that are very small spheres
evaporite (mineral)
minerals that may form by precipitation from aqueous solutiom under norma Earth surface conditions; for example massive gypsum or salt beds
extinction
the systematic absence of a related group of x-ray peaks in a diffraction pattern
obsidian
volcanic glass produced by the rapid cooling of a magma
general angle
a nonspecial angle between crystal faces or symmetry elements
fractional crystallization
separation of a crystallizing magma into parts by the successive crystallization of different minerals (see also partial crystallization)
polymerization
the connecting of polyhedra or other structural units chains, sheets, or networks by sharing or atoms
fluorescence
a type of luminescence that occurs when minerals are exposed to ultraviolet light, xrays, or cathode rays, but ceases when the exposure ceases
metamorphic
an adjective pertaining to the process of metmorphism
unstable (thermodynamics)
adjcetive describing a chemical system that does not have the minimum possible Gibbs energy; an unstable chemical system will react to obtain metastable or stable equilibrium if slightly perturbed
chemical weathering
type of weathering involving chemical reactions that transform or decompose miinerals and rock
alchemy
chemistry of the Middle Ages that combind science, magic, and philosophy
monoclinic
of or related to the monoclinic crystal system
birefringence (value)
the difference between the greatest and least indices of refraction
Weisseberg camera
an instrument for recording single crystal diffraction patterns on film
mineral formula
an expression that uses chemical symbols, parentheses, and subsrcipts to show the composition of a mineral
axis (rotational)
a symmetry element that relate identical crystals faces or other things by rotation of 60, 90, 120, 180, or 360 about an axis
Basalt
an extrusive igneous rock of mafic composition containing plagioclase as the only major feldspar; clinopyroxene plus or minus orthopyroxene plus or minus olivine are typically present (see also gabbro)
crystalline
having a crystal structure; having a regular arrangement of atoms characterized by a space lattice
Penetration twinns
crystals that pass through one another and often share the centre of their axial systems.
Wave Theory
visible light travels in a straight direction and vibrates at right angles, with components of: wavelength, amplitude, frequency and velocity
Calc-Alkaline
This type of rock is characteristic of a convergent plate boundary. It's found only in island arcs.
Fluid
This type of inclusion is formed when crystals leave spaces between them at high temperatures.
opaque
the inability to transmit light or to be seen through
ocular
a lens in an eyepiece of a microscope
reserves
ore that has been identified and that could be extracted at a profit
residual (mineral)
a mineral that has been concentrated in place by weathering and leaching of rock
wave front
the front, or leading edge, of multiple in-phase waves traveling in the same direction
Verneuil technique
a technique for synthesizing gems that involves melting powder and allowing it to accumulate and crystallize on a boule
uniaxial
a term describing a crystal that has only one optic axis; such crystals belong to the tetragonal or hexgonal crystal systems
ore mineral
a mienral, usually metallic, that is economically desirable
parent isotope
the initial radioactive member of a radioactive decay series
ductile
a term used to describe the tenacity of mienrals that are capable of being drawn into a wirelike shape
dop
a sticklike device that holds a gem crystal for grinding on a wheel
divariant field
a region on a phase diagram characterized by two degrees of freedom
chatoyancy
the play of colors seen in some minerals in which a silky sheen is seen to form a narrow band that changes position as the mineral is turned; for example cat's-eye chrysoberyl
crystal system
one of the six distinct coordinate systems: cubic, orthorhombic, tetragonal, hexagonal, monoclinic, and triclinic. The trigonal subdivision of the hexagonal system is sometimes counted as separate crystal system.
cyanide method
a method for extracting valuable metal ore that involves hydrogen cyanide
crystal structure
spatial arrangement of atoms or ions, and their bonds in a crystal
crossed polars
the condition caused when the upper polarizer is inserted in a polarizing light microscope
effervescence
a bubbling reacton; the term used to describe the reaction of calcite with dilute hydrochloric ace
lineage structure
a plane within a crystal separating slightly misoriented portions of a crystal structure
isogyre
a band of extinction in a interference figure that appears where light vibration directions are parallel and perpendiculoar to the lower and upper polarizers
critical size
for a nucleus to survive, growth must be rapid enough to overcome surface area affect
a "______ _____" is reached, when the crystal has a significant chance of not being redissolved
Crystal Epitaxis
Growing a crystal layer of one mineral on the crystal base of another mineral in such a manner that its crystalline orientation is the same
lower polarizer
a fixed polarizing lens located in the substage of a polarizing light microscope
Cartesian coordinate system
an X-Y-Z coordinate system in which all axes are at 90degree and the unit distances along all axes are equal
brucite layer
a sheet of Mg(OH)6 octahedra in a layered crystal structure
body diagonal
aline passing through the center of a cube or other three-dimensional geometric shape and connecting opposite corners
univariant line
a line on a phase diagram; generally representing a reaction and having one degree of freedom
bauxite
name given to a rock or a mineral-like material composed primarily of a mixture of aluminum oxides and hydroxides such as boehmite and gibbsite;l bauxite is the most significant aluminum ore
optic normal interference figure
the interference figure obtained when looking down a optic normal
oxidation
the process of an atom losing one or more electrons through chemical reaction
index (x-ray pattern)
to assign appropriate (hkl) vlaues to x-ray diffraction peaks
hexagonal closet packing
closest packing of spheres in an orrangement similar to a hexgonal prism with three extra spheres in its interior; equivalent to stacking closest packed layers in an ABABAB sequence
Haiiy's Law
a law that states that crystal faces make simple rational intercepts with crystallographic axes; a corrolary is that crystal faces have rational and general small Miller indcies (see also Law of Rational indices)
halogen
elements (such as F, Cl, and Br) in the seventeenth group of the periodic table of the elements; halogens typically ionize to become monovalent anions
reduce
said of an element; to gain one or more electrons
dodecahedron
a closed cubic form of 12 faces that may have any of a number of shapes and point group symmetries
Mississippie Valley-type deposit
an epigenetic ore deposit hosted by carbonate rocksl typically, a source of lead and zinc
screw dislocations
a face can lead to very fast growth this leads to elongate habits (acicular, needles, fibrous)
angle of incidence
the angle that an impinging ray makes with a normal to an interface
essential mineral
a ineral in a rock that is necessary for the rock to be classified or named as it is
cover slip
a thin piece of glass that is placed over grains and liquid to make a grain mount
cubic closest packing
closest packing of atoms in a pattern similar to a face-centered cubic lattice; closest packing equivalent to stacking closest packed layers in an ABCABC sequence
Hydrogen Bond
A bond formed by a hydrogen atom to an electron negative atom
body centered
said of a unit cell that has an extra lattice point at its center
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