Generally it's only the wizards that deal with the physical side - such as rock shapping and rock combining - that get magic smoke, though if they did their part wrong the wizards that make rocks think might get it as can the people playing Skyrim using the thinking rocks.
You have to melt the whole thing back to raw rock and remake it from scratch, which is usually more work than just grabbing some fresh raw rock to build a new one so it's seldom done.