the available depth (near flush to max of about 1/8 inch) does not lend itself to a marble or granite inlay.
this is a nice house, but not by any stretch a mansion deserving of restoration to original specs at any cost. (brick veneer over concrete block walls for the exterior, all interior walls of concrete block; nice to have in an area of termites and rare but possible flooding from hurricanes. cathedral ceiling of tongue-and-groove 2x6, and 42 ft of near continuous plate glass windows in the 'public' area of the house. attractively positioned on 6 acres.)
the best we have come up with so far is to:
..square off the offending area with a concrete saw;
..fill to level with thinset mortar;
..finish with epoxy paint of a creme color.
if we could find out more about terrazzo, get hold of the right tools and materials, and thought the dust raised by polishing would be manageable, we might try that.