The other is to put them in a magma proof bin (such as steel), immerse it in magma (don't try this with lignite or bituminous coal, it creates dwarven fire), remove the magma, let it cool, and the liquid rocks should re-solidify into solid stone instead of stone blocks.
This doesn't actually work - what it creates is a
glob of Stone (adj)* which cannot be used for anything (and will probably be removed on the next season change), as opposed to an actual stone. If you saw this on the wiki, the wiki is actually
incorrect in this case (and will be updated shortly).
* if you try this with something made of gold metal, you'll get a puddle of Molten Golden, which will cool and solidify into a glob of Golden