I am a science teacher, amateur meteorite collector, and sell Tungsten Carbide Jewelry on side. I had these made a friend who makes my Jewelry and thought I would offer them to the Meteorite community at very good prices. I do not believe in ridiculous mark ups. (These have been sold by others in Tungsten carbide, Brass, and Aluminum) Tungsten carbide is harder and much more durable that either brass or Aluminum.
My black plating is Titanium aluminium nitride. BOnded to the Tungsten Carbide by a PVD process. http://en.wikipedia.org/wiki/Titanium_aluminium_nitride
as this is a plating it is not as strong as TiALN by itself it is not permantly (as with all plating processes) bonded to the Tungsten Carbide but it is much much more durable (many many times) than Enamel Paint. I will not (if possible) ever use Enamel paint (unless as a inlay under a clear protective coating) on any of my products.