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Click Here For Best Selection Of High Quality Polarizing Microscope

Click Here For Best Selection Of High Quality Polarizing Microscope

There can be some instances wherein thin section sample are imperfectly prepared. This is most often the case with beginner mineralogists or students. Imperfectly prepared samples in thin section may possibly contain variety of materials that may be incorrectly recognized as mineral. The presence of the non-mineral materials can actually complicate the identification process. The most common non-minerals found in thin section samples are bubbles, textile fibers, and grinding abrasive.

            Bubbles that may be possibly trapped in the cement are almost inevitable unless proper and extra care in sample preparation is done accordingly. The complication that bubbles may bring is that, if it has been trapped at the portion where a grain has been plucked out, this bubble may be possibly mistaken as an indication for a high relief isotropic mineral. Also, under orthoscopic illumination, small spherical bubbles may display a uniaxial cross look like image.

            Abrasives can also look like fine angular opaque grains that are distributed throughout some imperfectly prepared sample. The abrasive will surely be embedded in the cement if the cement is not entirely cured before grinding.

            Textile fiber materials, on the other hand, may appear as elongate fibers. Examples of this are the textile materials from clothing, paper towels, and others. Between crossed polars of petrographic polarizing microscope, these textile fiber materials may display interference color because some varieties are anisotropic. However, these materials can be easily determined if in the cement or either above or below the sample when evaluated closely with the careful adjustments on the focus of the polarized microscope.



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Monday, March 24th, 2008 at 4:23 am
Category:
Optical Mineralogy
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Click Here For Best Selection Of High Quality Polarizing Microscope