Not much you can do about it.
Marble tile turning orange.
The aforementioned conditions plus the stone being subjected to excessive moisture can cause rust staining or also know as inorganic metal stains.
The second cause is excess iron in the water.
Marcescens is commonly found growing in bathrooms especially on tile grout shower corners toilet water line and basin where it manifests as a pink pink orange or orange discoloration and slimy film feeding off phosphorus containing materials or fatty substances such as soap and shampoo residue.
It is for this reason that we recommend not using white marble in a shower.
Well they can either be mold or iron in the water that is discoloring your grout.
If iron is present in the marble tile it will begin to oxidize when exposed to water or other oxidizers such as acids and household bleach.
Answer orange or rust like staining in stone can be caused by minerals within the stone or sometimes because the stone is in close proximity of metal.
Try to clean it pull it out with a poultice will make it worse.
My initial guess is that the orange stain is water damage geting under the tile maybe from the fact there seems to be no silicone joint or the fact there may be pipes in that area possibly with aleak.
It is for this reason that we recommend not using white marble in a shower.
The first cause is mold which develops from the combination of moisture and warmth in the bathroom.
If the marble becomes wet long enough to allow moisture to leach through the marble the iron deposits will oxidize creating yellow orange brown stains.
It is rust stains that naturally occurs when the iron deposits reacts with water or repeated long term exposure to moisture.
Orange discoloration on the tile grout in a bathroom has a couple of main causes.
First of all what are those orange stains in your grout anyways.
Iron can stain the bathtub and other light colored fixtures that the water touches.
In my case i believe it to be iron in the water since we have tried cleaning this tile to no avail for quite some time.
Kbaby what is that to the left of the orange mark in the picture.
You can recommend that your friend pulls the 3 4 tiles out and replace them.
Due to its abundant presence in the environment and its preference for damp conditions s.
Usually it this process occurs over a longer period but if enough moisture it could happen quickly and these tiles are thin.