OM and Petrography Flashcards
Used extensively to examine transparent minerals, fragments, grains and small crystals, as well as thin sections of minerals, rocks and other crystalline aggregates
Polarizing Microscope
cut to such thickness that it increases or decreases retardation of a section by about 1/4λ
Mica Plate
It is used to determine fast and slow directions (electric vectors) of light polarization in crystals under view on the microscope stage by increasing or decreasing retardation of the light
Gypsum Plate
beam of light consists of a stream of minute particles, or photons, given off at high velocity by a luminous body that travel through space in straight lines and eventually reach the eye.
Corpuscular Theory
useful in the determination of the optical properties of individual crystals or aggregates and in the interpretations of textures, structures, growth patterns, and various relationship of natural or artificial substance.
Polarizing Microscope
considered light to be transmitted by the vibration of particle in the waves. The phenomena of light such as reflection, refraction, diffraction and interference may be readily explained in accordance with this theory.
Wave Theory
ground to produce interference colors from the beginning of the first to the end of the third or fourth order. Equals 0.009
Quartz Wedge
He is the proponent for the Wave Theory
Christian Huygens
considered light as made up of waves but said that waves are electromagnetic. A wave consists of rapidly alternating electric and magnetic fields normal to each other and normal to the direction of propagation of light
Electromagnetic Theory
He is the proponent for the Electromagnetic Theory
James Clerk Maxwell
assuming that radiating oscillators in a black body radiate energy discontinuously in units
Quantum Theory
black body that radiate energy discontinuously in units are called
Quanta
defined as the locus of all the points of a medium, which receives light wave disturbance simultaneously so that all these points are, in the same phase
Wave Front
a perpendicular drawn to the surface of a wave front at any point in the direction of propagation of light
Wave Normal
The direction in which light is propagated
Ray of Light
the wave normal and the direction of propagation of the light rays are perpendicular to the wave front
Isotropic
may represent a curve combining movement around a circle with motion along a straight line
Displacement
lies in the wavefront and is perpendicular to the ray in isotropic media. In anisotropic media, it is only perpendicular in limited directions
Vibration Direction
The light rays are not parallel to the wave normal
Anisotropic
distance between two successive crests or troughs, or any corresponding distance along the wave.
Wavelength
surface determined at a given instant by all parts of a system of waves traveling along the same direction and in the same phase. In anisotropic, it is perpendicular only in certain directions.
Wavefront
direction perpendicular to the wavefront. In isotropic, the wave normal and ray direction are the same. In anisotropic, they differ aside from certain directions
Wave Normal
number of vibrations in a given unit of time
Frequency
maximum displacement of a wave from the line of transmission
Amplitude
time interval necessary for a wave to undergo a complete oscillation
Period
point of the wave with the maximum upward displacement
Crest
point of the wave with the greatest downward displacement
Trough
a group of light waves following along a sample path
Beam
straight-line path followed by light in moving from one point to another
Ray
equal to the ratio of the wave-normal velocity in a vacuum to the wave-normal velocity in the medium whether isotropic or anisotrophic
Refractive Index
light of a single wavelength
Monochromatic Light
lies parallel to the plane of the wavefront. In isotropic, perpendicular to the direction of the propagation. In anisotropic, still parallel but not perpendicular to the direction of the propagation
Light Vector
measures the electrical displacement
Electric
measures the magnetic displacement or induction
magnetic
combination of all the different wavelengths visible to the eye. Maybe considered composed of seven different colors
White light
speed of light
186,284 mi/s
realistic virtual image with a flat field
Orthoscopic Observation
Low to high magnification objective
Analyzer out
Condenser top lens out
Bertrand lens out
PPL or Plane Polarized Light or Uncrossed Nichols
What solution is used to clean the thin section?
Xylol Solution
High magnification objective (40x) Analyzer in Condenser top lens in Bertrand lens in Accessories in
Conoscopic Observation
Study of the interaction of light with minerals
Optical Mineralogy
Low to high magnification objective
Analyzer in
Condenser top lens out
Bertrand lens out
XPL or Cross Polarized Light or Crossed Nichols
yields interference figures which represent an optical pattern caused by the behavior of light in individual crystal
Conoscopic Observation
Study of opaque minerals commonly studied in reflected light
Ore Microscopy
observed w/ plane prolonged light; not always the same as megacopic color
Color
change in color of a mineral in varying degrees as the stage is rotated due to differences in light absorption & extraordinary rays generally expressed as a formula
Pleochroism
the ability of a mineral to separate into smaller particles bounded of faces of possible crystal form. Expressed or best explained in terms of direction
Cleavage
can be expressed by using the terms eubedral subhedral anhedral; lath-shape, bladed etc
Shape and Form