I watched an episode of Modern Marvels on the hisory channel all about
marble. Mining, cutting, carving, everything you'd ever want to know
about marble.

One annecdote from a marble company spokesman said when you take an
antacid pill, you're eating marble. Calcium carbonate! I thought WHAT?
But it's true.

Sea shells (a limestone of a sort) and almost entirely calcium carbonate
collected to form marble over thousands of years.

So when you take a calcium supplement or need a Tums to neutralic stomach
acid, you're eating marble dust!

Visit: http://en.wikipedia.org/wiki/Calcium_carbonate and click on the
Uses link.

Who'da thunk!

Andy