[jacquesm]

> for the coarser grits (< ~3000)

I love it how you casually throw that out there. For the un-initiated, outside of grinding lenses: grit 3000 is approximately 6 micron particles and very fine indeed but for this purpose (and gem polishing) it is still considered 'coarse'.

The finest polishing grits go to 100,000, ~0.25 u across.

[dom0]

And for knife sharpening people: 3000 grit (and a leather strip) is enough to almost reach razor sharpness ... with good steel, that is :)