Stains leaching through from cement on marble fireplace

Q. We have just had a fireplace installed by builders (who I must admit were not specialists) and the cement they have used seems to have left behind orange stains on our Marble fireplace. It is now two days after installation and the stains are reducing in intensity (I imagine as the cement dries) but they are still quite visible. I would like to know if this is normal and whether the stains are likely to completely disappear. If not, what you would suggest to help get rid of them as I get the feeling a simple cleaning product may not do the job. Thanks in advance.

 

A. Its difficult to tell without see a picture. However if they are disappearing it is very possible it is just moisture. If the spots don't completely disappear in a week then you may have what is called iron oxidation. In other words the stone is rusting due to moisture. If this is the case I am afraid the stone will need to be replaced. You need to ask them what they used to set the stone with, since certain setting materials can also cause this problem.