These stains can be the result of a water glass that was left on a marble countertop for too long or from hard water buildup around sinks and showers.
Yellow stains on marble tile.
White marble tiles can remain for years without yellowing then over time may slowly turn yellow and in severe causes may turn completely brown.
This oxidation process is accelerated when the tile is saturated as in the flood in the above example.
Mold is a common problem in many bathroom settings.
Usually the problem occurs in showers and on floors because there is water under or behind the tiles.
Sometimes checking for moisture is important because water content in marble tiles is a clear indication that soon the material may turn yellow with iron beginning to oxidize.
This process of oxidation is similar to the rusting of metal.
You only need to cover just past the actual stain.
The paste should be about 1 4 to 1 2 inch thick.
White marble tiles can remain for years without yellowing then over time may slowly turn yellow and in severe causes may turn completely brown.
Spread the baking soda paste in a thick layer on top of the stained marble tile.
Water stains are yet another common stain that occurs on marble.
If water leaches into the core of the marble tile and contacts these deposits the iron will rust and bleed to the surface causing brown orange or yellow spots marble stains.
Iron stains however can be eliminated by mopping away water as accumulated in the marble tiles in order to prevent the iron from getting oxidized.