Somehow, I was editing, and lost my text.  The above were the first pics of Gems I took with the Foldscope.  As a Gemologist, I was curious if this tool would be good for field gem ID, and detecting natural from synthetic.  The pink photo shows a liquid inclusion, proving that I was looking at a natural 1mm Ruby.  The green photo was a natural Emerald, as evidenced by the black chromite inclusions, liquid inclusions (look like bubbles), and rusty iron deposits.  My focusing got better as I got further into my study.

This is the natural Emerald from the above photo (it was on a slide when photographed at low mag).  Could not get the Ruby pic to load.  The right shows how I prepared slides.  I most used 1-3mm tiny gems, and affixed with CA onto a glass slide.  For the most part, if the object was translucent/transparent enough for light to pass through, I got good pics.  Magnification was great and I could definitely tell natural from synthetic.  I also tried some loose stones, held with tweezers in the slide gap, and larger pieces….detailed that in other posts.