I'm about 2 weeks behind in mail but prior to becoming a teacher 2
1/2 years ago, I worked as a painter and a sculptor. My stone was
sandstone and I had several varieties to work with.
In my opinion this is not a task for school kids unless you can
afford the proper safety equipment. Sandstone contains silica in it's
dust and each carver should have a real mask (not just the
fiber/cotton ones you buy in 3 to a pack) as well as ear and eye
protection, leather gloves and probably a good apron, as stone chips
will fly everywhere. To rough out the stone, I used a 3 pound lump
hammer and various hand held chisels in point, chisel, & claw tip.
These tools were hand made from tempered steel and are about 8-12"
long and weigh about a pound each. You might find them cheaply at a
yard sale but I had mine made by a metalworker. You should not use a
dremel tool because it raises too much dust. I also used raspers in
various forms for smoothing the stone. I also used an air compressor
and tools but prefer the finish the hand tools offer.
Pounding the stone takes considerable fitness and strength and is
very dirty and dusty - suggest you work outdoors on some heavy
stumps of different height levels.
I would be glad to answer any questions you might have on this -
perhaps I take it too seriously - sorry if I sound didactic.