That sculpture was done using a Foredom Flex Shaft and Diamond points...similar to a dentists arsenal.
The lapidary grinding and polishing and buffing Is accomplished with a progression of Silicon Carbide
Grits like 100 >>220>>>400>>>600>>>1200>>>>then polish steps
Wheels,belts and Water for cooling.....the polishing is done with things like aluminum oxide,
Cerium Oxide , linde polish... using a slurry of water and a rapidly spinning moist leather pad....
Some opt for diamond impregnated pastes to walk thru to the polish...and for good reason.
You must clean in between grit progressions else you will contaminate your work and ruinate it...