[Rockhounds] sphere-makers: how do you make very tiny spheres?

[DonH]

Hi,

I know some of you make spheres, usually of the 1/2" to 6" (or whatever) 
variety.  I know how these are made and have seen the equiment.

However, is anyone familiar with making extremely tiny spheres, less 
than 1 millimeter in size?  I would imagine the milling process as I 
know it doesn't scale down that small.

Thanks,
Don