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.
The glass stone's colors divide into three areas.
The largest area is the basic color of the stone. In my example I painted a
green stone, so the basic color is a deep dark green, to simulate the depth of
the glass stone. As this glass stone gets thinner to it edges the green gets
lighter to simulate the lesser deepness of the material. In the lower area of
the gemstone the light of our imagenary light source will gather and lighten up
the material and the gemstones base. This is our second area. To simulate this
I paint halfmoon shaped layers of lighter greens onto the lower area. Every
layer is a bit smaller in shape and lighter in color. I use a wet on dry
blending to make a transition from the darker green edges to the lightest
center. Now the gemstone is almost finished. The last thing that is missing,
and is most important for our gemstone-effect - and area No.3 - is the tiny
spot that will show on the surface ot the gemstone as reflection from our
imaginary light source.
To accomplish this I paint a tiny white spot onto the upper area of the
gemstone. Right there where the green of the gem is the darkest and deepest.
This spot can have the shape of a kidney to make the gem's surface look even
rounder and more raised. Though this may look better on a 2D gem then on a 3D
miniature. Just experiment a bit with the size and position of the light spot.
You can paint the gemstone in virtually every color you like. Even in black and
white if you use only greys and black.