Tutorial : How to paint shining gems
Basically painting a gemstone or any glass like or crystal structure on a
miniature is to recreate the light effects and reflections of the gem stones
material. As one is not truly able to paint the transparency of glass, the
painter has to simulate the effect an imaginary light source has on the
transparent gemstone. A good point to start is to take a look at one of those
little glass stones often used as counters for collectible card games like
vampire or magic.