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.
Marble stain test.
When testing with mineral oil know that mineral oil will evaporate and is not an indication that your marble or granite is damaged but rather that it needs marble sealing.
How to remove ink stains and paint stains from marble surfaces you can use lacquer thinner to get ink stains from markers pens etc and small amounts of paint out of marble.
More persistent ink stains and larger paint stains can be removed with the help of a marble poultice that will soak up the pigments from the stain within a couple of days.
Mold can stain marble bathroom countertops floors etc.
The stain gets more pronounced as time goes on increasing in size and darkening in color.
Even after 10 minutes we can see the residual stain from the olive oil.
Water stains are yet another common stain that occurs on marble.
This can be restored by your marble contractor.
Due to the oils and acidity in the olive oil the marble is actually etched meaning the sheen from the marble is pulled out of the stone.
Mold is a common problem in many bathroom settings.