polarizing microscope

(redirected from Petrographic microscope)
Also found in: Dictionary, Encyclopedia, Wikipedia.

po·lar·iz·ing mi·cro·scope

a microscope equipped with a polarizing filter below and above the specimen that forms an image by the influence of specimen birefringence on polarized light; the polarizing direction of the two filters is typically adjustable, which, together with a graduated rotating stage, permits measurement of the angular value of different refractive indices in either biologic or chemical specimens.


an instrument used to obtain an enlarged image of small objects and reveal details of structure not otherwise distinguishable.

acoustic microscope
one using very high frequency ultrasound waves, which are focused on the object; the reflected beam is converted to an image by electronic processing.
binocular microscope
one with two eyepieces, permitting use of both eyes simultaneously.
bright-field microscope
the standard bench microscope used in histology and requiring stained tissue sections.
compound microscope
the standard laboratory microscope used in veterinary science; consists of a two lens system whereby the image formed by the system near the object (objective) is magnified by the one nearer the eye (eyepiece).
darkfield microscope
used for examining unstained, often living cells, in which light is only directed into the objective lens if it is deflected by an object in its path. The object is thus viewed as a white structure in an otherwise black (darkfield) background.
electron microscope
one using an electron beam of very short wavelength as the source of illumination. It has a resolving power of 2 nm (which is 100 times greater than with the light microscope). Includes the transmission electron microscope and the scanning electron microscope (below). See also immunoelectron microscopy.
fluorescence microscope
one used for the examination of specimens stained with fluorochromes or fluorochrome complexes, e.g. a fluorescein-labeled antibody, which fluoresces in ultraviolet light. See also fluorescence microscopy.
interference microscope
a microscope similar to the phase contrast microscope but delivers a three-dimensional image. Called also Nomarski interference phase microscope.
light microscope
used for examining unstained or stained particles or the cellular structure of tissues that have been cut into sections and stained. It has a resolving power of 0.2 μm. Modern light microscopes have an eyepiece and objective lenses which provide magnification, and a condenser beneath the stage which gathers and focuses light on the object being examined.
operating microscope
one designed for use in performance of delicate surgical procedures, e.g. on the middle ear, eye or small vessels of the heart.
phase microscope, phase-contrast microscope
a form of light microscope useful for examining living, unstained structures, including animal cells and bacteria, e.g. leptospira. The phase of the light wave passing through different structures in the cell, e.g. nucleus vs. thin part of the cytoplasm, is changed by different amounts and thereby provides contrast.
polarizing microscope
based on the phenomenon of birefringence; useful in the study of bone and muscle.
scanning electron microscope (SEM)
an electron microscope that produces a high-magnification image of the surface of a metal-coated specimen (shadow casting) by scanning an electron beam and building up an image from the electrons reflected at each point. Particularly useful for determining the three-dimensional structure of objects.
simple microscope
one that consists of a single lens.
specular microscope
one used in the examination of the corneal endothelium.
stereoscopic microscope
a binocular microscope modified to give a three-dimensional view of the specimen.
surgical microscope
see operating microscope (above).
transmission electron microscope, TEM
one that resembles an inverted light microscope in that the beam of electrons generated from a heated filament at the top of the instrument passes down through a column where it is focused by magnetic coils (lenses) and is differentially scattered when it passes through the specimen. The image is recorded either on a photographic plate or on a phosphorescent screen.
ultraviolet microscope
uses an ultraviolet light source; useful in histochemical studies; only photographic images are available.
References in periodicals archive ?
Carl Klein gained recognition as a crystallographer at several German universities and was an inventor of a great many crystal rotating devices mainly to be employed with petrographic microscopes.
Application of new and old analytical instrumentation continued with Ward utilizing the petrographic microscope to study hydration products (56).
Dan Kile has written numerous articles for Rocks & Minerals and The Mineralogical Record, including a monograph on the history of the petrographic microscope, published as a special supplement to The Mineralogical Record.
He was held in high esteem particularly for his work with the petrographic microscope.
Authors thanks the Department of Geological Sciences of Universidad Nacional de Colombia which allowed the use of petrographic microscopes and other equipment.
Observed under optical and petrographic microscopes in the Company's mineral observation laboratory in Bamako, the diamond is a clear white gem with hardly any impurities.
Dan and Dianne Kile got away from displaying minerals and put in a wonderful display of petrographic microscopes and accessories used in mineral identification.