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Click Here For Best Selection Of High Quality Polarizing Microscope

Click Here For Best Selection Of High Quality Polarizing Microscope

In the field of optical mineralogy, the optical properties of minerals are known or most clearly explained in reference to the electromagnetic theory of light. The electromagnetic theory of light states that light may be discussed in terms of wavelengths and vibrations perpendicular to the direction of the propagation. It has been known that white light comprises a gradational series of wavelengths from violet to red. And this can be actually separated into its component colors by the well-known triangular glass prism. It has been also observed that the vibrations of the ordinary light take place in all direction. Polarized light on the other hand vibrates in only one direction perpendicular to the propagation direction.

            Polarized light is produced by the polarizer and analyzer. These polarizer and analyzer are accessories to modern polarizing microscopes like the ones used in the field of optical mineralogy. A polarizer is actually a sheet of plastic Polaroid that absorbs all light except the ones vibrating in only one direction. It has been known in the field of optical mineralogy that a natural tourmaline crystal also absorbs light vibrating in all but one direction. Thus, natural tourmaline crystal can be used as a simple polarizer for simple microscopes.

            When examining specimens under a petrographic polarizing microscope used in the field of optical mineralogy, it can be done in three ways. First, evaluate using the ordinary light. Second, examining the material in plane-polarized light where light is polarized by the polarizer placed below the stage of a polarizing microscope before passing through the specimen on the stage. Third is evaluating the specimen in crossed-polarized light. In this set up, aside from the polarizer used, an analyzer is being inserted. Thus, the light that may pass is then polarized after as well as before passing through the specimen. These two sheets of Polaroid are carefully oriented so that they could transmit light vibrating in the directions at right angles to each other. Thus, they absorb all light passing through the microscope.



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Thursday, April 16th, 2009 at 2:32 am
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Optical Mineralogy
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Click Here For Best Selection Of High Quality Polarizing Microscope