While visiting museums in Europe this year, I was continuously perplexed by how intricate and smooth ancient sculptors could make their statues. I finally took the time to look up the process, and this is what I found
"Carving Marble with Traditional Tools"
The video shows how to carve marble using the tools that ancient sculptors would have had at their disposal. Their tool-belt would include several types of chisels (one of which uses a ridiculously awesome string contraption, see 1:45 in the video) for both coarse and fine revisions and a sanding instrument called a rasp, which reminds me of a cheese-grater.
In modern sculpting, they use similar instruments with the addition of calipers and a few different types of mallets to more easily regulate the amount of force applied to the chisel. Here's a video:
"The Making of a Marble Statue"
This video includes horrifying videography (almost appears to be stalking the sculptor at around 2:00), but is nonetheless informative and worth the view.