Minor blemishes in marble caused by stains or scratches can be corrected by a good grade polishing powder or tin dioxide, available at most leading monument or household maintenance stores. Rubbing in the powder with a properly mounted piece of felt and waxing over the affected area should do the trick.
However, marble’s extreme porosity makes it susceptible to more serious damage, like easy chipping, cracking or breakage. Where actual pieces of marble have broken away, the separated pieces should be located and all edges wiped down with acetone. This will remove all foreign material and facilitate proper bonding with glue. You can choose regular epoxy glue or professional marble repair cement to stick the piece/s back into place. This is a fairly straightforward process which works much better with marble than with many other materials. Two precautions must be taken – first, ensuring that there is no excess glue which will mar the surface after the glue has hardened, and second, making sure to apply sufficient pressure for long enough to ensure a perfect join.
If the pieces from the chipped or broken corners in marble blocks or tiles can’t be found, the marble must be reformed with material closely resembling the surface. The exact contours of the broken pieces must be retraced by a makeshift mould lined with wax paper. When this is done, a mixture of marble dust and polyester resin cement can be used to fill in the missing piece. It will harden into the desired shape. If this is done properly, the regenerated piece will be indistinguishable from the original.
The same marble dust/resin cement mix can be used to fill in holes in marble. The ratio of marble dust and resin should be calibrated to best imitate the shade of marble in question.
Fixing marble surfaces can be a fiddly affair, but taking the time to do it right will pay off – your marble will look like new!