It is not a problem with the tile but the installation or perhaps a serious water leak.
Marble tile getting darker.
Cement board still allows water to pass through.
The top picture was taken right after the install the bottom is after about two.
Most mastics turn brown over time when exposed to air.
Because marble is porous you should clean spills immediately or you run the risk of the stone developing stains.
If you notice that the tiles in your wet area especially in the shower recess where you may have a leaking shower have changed to a darker colour the situation needs attention as soon as possible.
Instead it just absorbs into the marble.
Marble a crystallized form of limestone is a popular choice for worktops flooring and wall tiles in both kitchens and bathrooms.
Marble tile is just as susceptible to staining as solid marble but you can use the same method.
The problem is most likely a bad installation and or cracks or voids in the grout allowing water to get trapped behind the tiles where it cannot evaporate.
If you try these methods and still do not have.
Since i know very little about tile and plumbing i had everything professionally installed.
Please please do consider using kerdi everywhere from and for the floor pan and up onto the walls as far as the walls could possibly get wet.
What type of thinset to use when installing marble tile.
If anything the marble will get darker as time goes on and the mastic continues to cure.
Rust stains can usually be removed with a poultice or a non acidic rust remover.
Marble shower tile getting darker.
Available in a variety of colors and shades marble can be.
I had tile installed i my bathroom.
When installing tile in your home you can use a variety of products to adhere the tile to the substrate.
If it was a tub with shower is one thing but a full shower requires the extra moisture protection especially at the base.
Marble is a durable stone under most circumstances but it does require some special care.
Wet stone is always darker in color so the white marble tiles become gray and stay gray since they are saturated with water.
It is an indication of a problem that can cause long term structural damage if left unattended.
It is a beautiful marble basket weave pattern but it is turning dark.
Be careful if you are removing a stain from darker colored marble as hydrogen peroxide can cause the marble to lighten.