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Cross Polarized Light Microscopy     Polarizing microscopes have many advanced features that ordinary scopes do not such as excess light capacity, revolving polarizing analyzers, compensators, retardation plates, rotating  specimen holders and incident (reflected) lighting. Although all of these  features are useful, most are not absolutely necessary for great photomicrographs. Since a quality thin section is critical to good photomicrographs, select the thin section carefully. I have to say, I have never been disappointed with any of the thin sections I have purchased from reputable meteorite dealers. I have however, bought some "bargains" that are completely unusable. They might be good for a micro mount collection but they should go nowhere near a microscope. It drives me crazy that I, (just a hobbyist) would put a better polish on a large hand sample than I have seen on some samples sold as "thin sections". Thin section quality can vary greatly and you need to decide on whether you want covered or not. Covered is when a glass cover slip is epoxied over the sample. A good covered thin section will last a lifetime, but they aren't very useful to view in cross polarized transmitted (pass through) light combined with incident (reflected) light. Uncovered thin sections are, but they are more delicate and vulnerable to humidity. Most problems with thin sections can't be ascertained until it is on a microscope. Just be aware that if you are having problems, it may not be you or your microscope. Try a new supplier until you get the quality you need.
Salvaging poor thin sections is seldom possible as every thin has two sides and one is glued face down. Making your own thin sections is easy in principle, but very difficult to do well. It is only a 30 micron piece of meteorite glued onto a glass slide. Since an understanding of what goes into making a thin is both interesting and helpful in evaluation of thins you may be considering to buy, I'll go over the basics, but this is an overview, not a guide! I have made a few myself but I am not an expert nor am I even that good. First, the sample is polished and taken down in steps, allowing enough polish time to remove the sub-surface damage caused by the  previous grit. After the first few grinding steps epoxy is applied to the face of the sample and allowed to set before the finish polish steps are started.  This helps reduce crystal fragment "plucking". The polished sample is epoxied onto a glass slide. (A vacuum chamber mounting press is handy but a clamp will  often work fine.) After setting, the excess is cut off using a diamond saw. Trimming the sample thin is essential to avoid excess grinding time, however, to avoid damage to the sample structure, it should be trimmed to no less than 500 microns.