Fabricating a Marble Edge

I have found some marble tile that I would
like to use on a raised fireplace hearth. I
am told that the edge can be "fabricated",
i.e. shaped. I talked to someone at a
marble company and in order to verifiy that
the edge could be fabricated, he simply ran
a sander over it and commented that I could
actually do this myself. Now my question -
the tile is 1/2" thick and I would like to
have it 1" thick. What adhesive would be
best to adhere a piece below the edge to
bring it up to 1" before I start "fabricating"?