Last time I was at my FLGS, the owner showed me a showed me some dice he just began to carry, by a company called Game Science. The goal of the company is to make the most random rolling dice possable. I purchased a set to test out.
My test was series of twenty rolls on my new coal black d20 and my orignial TSR D&D d20 with a diviot in it, here after called 'Old Blue'.
The new die, only repeated the same number 3 times. The rest were spread out quite evenly. On the other hand, Old Blue rolled along the band that has 16, 8, 10, 12, 15, 5, 13, 9, and 6. This leads me to conclued that the Coal Black die is round, therefore random and that Old Blue is oval in shape and rolls like poo.
Yes, I do know that this wasn't the most scientific test but I could see the pattren emerging. I recomend these dice, because you should have the right tools for the job.