Ground and powdered gemstone have been used for quite a long time as
a pigment for paints. Although their use is more limited these days,
some traditional painters still prefer to mix their own pigments, and
incorporate gemstones into their paints. You will need to use whole
not "swarf," to do this. You can use broken or chipped
stones, low-grade stones, or rough material. There is no need to use
fine gems for this.
You will need to crush your stones into a powder. You can use a
mortar and pestle on softer stones, but you will find that beryl and
corundum will also wear away part of your mortar and pestle, ruining
your pigments. There are special grinders used for this, made of
hardened steel. They work on a principle similar to a millstone.
I know a painter who does grind his own pigments and uses gemstones
in his paints. If you are interested in pursuing this, I can find out
where you could purchase the equipment needed.
16639 Raven Rock Rd.
Sabillasville, MD 21780