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Click Here For Best Selection Of High Quality Polarizing Microscope

Click Here For Best Selection Of High Quality Polarizing Microscope

The color of light that is not absorbed on transmission or reflection is making up the color of the mineral or of any other object that is of very concern in the field of optical mineralogy. Most of the time, when a mineral is evaluated both in reflected and transmitted light of the petrographic polarizing microscopes, the color exhibited by the object in usually the same. But of course there are some few exceptions. When all of the visible spectrums are essentially reflected, the white object would certainly appear white under polarized microscope. Similarly, all of the visible spectrums are also essentially transmitted by a clear mineral. All wavelengths of light are on the other hand are absorbed by a black object. A mineral would appear colored when it selectively absorb certain wavelengths of light and transmit or reflects the remaining light to our eye. The kind of wavelength transmitted to the eye and the process on how the eye interprets these wavelengths affects the perception of the color of the mineral that is being evaluated under petrographic polarizing microscopes. Under a polarized light microscope, a number of different minerals may appear to be of the same color even though they each reflects a different complement of wavelengths to the one observing under the microscope.

It is also important to note that the perception of the color of the mineral is not an inherent property but it depends particularly on the color of the incident light of the polarizing microscope being used. For instance, an object that is perceived white in white light would appear blue in blue light, yellow in yellow light, and so on. This is because these are the only wavelengths of light that are available to be transmitted to the observer. When monochromatic light is used for evaluation, a colored mineral may appear black unless of course if they are capable of reflecting or transmitting the wavelength of the monochromatic light. These important observations are of the concerns of optical mineralogy.

When evaluated on atomic scale, the colors of light that a mineral absorbs are dependent on the interaction between the natural resonance of the electron clouds around each atom and the electric vectors of the light. The light is transmitted as previously described when the frequency of the light is significantly different from the natural resonance. On the other hand, the matter absorbs the light if the frequency of the light is nearly the same as the natural frequency of the electron clouds. Abnormal dispersion can be also found exhibited by lights having frequencies that are showing strong adsorption. This absorbed light energy is usually converted into heat energy. Dark-colored minerals usually heat up much faster than pale-colored minerals when exposed to sunlight or other sources of light because they absorb more of the light than the pale-colored materials.

Wednesday, February 27th, 2008 at 3:49 am
Optical Mineralogy
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Click Here For Best Selection Of High Quality Polarizing Microscope