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Click Here For Best Selection Of High Quality Polarizing Microscope

Click Here For Best Selection Of High Quality Polarizing Microscope

It has been observed in the field of optical mineralogy that the several grains of a mineral in a thin section will normally be cut parallel to different crystallographic directions, and hence intersects the indicatrix in different orientations. The interference color as observed with the aid of polarizing microscope for mineralogists will vary from black or very dark grey for those cut parallel to a circular section of the indicatrix, to a maximum for those that are cut parallel to some other known directions. Therefore, for a mineral with birefringence E in a mineral section with thickness D, we may be able to see a number of grains with interference colors ranging from 1 to 7. It is important to note as observed in optical mineralogy that to measure the true birefringence we must therefore search for the grain with the highest interference color. The search must be thorough. A problem arises if the mineral has a preferred orientation, as is often the case in metamorphic rocks, when suitably oriented sections may not be found present.

 



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Friday, October 30th, 2009 at 2:51 pm
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Optical Mineralogy
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Click Here For Best Selection Of High Quality Polarizing Microscope