Natural stone surfaces in a wet environment can emit “efflorescence,” or a rough crusty like coating that can be unpleasant to stand on. Explained this way, imagine going into a wet cave that has stalactites and stalagmites with water dripping from them. This is a similar condition a stone surface can develope. And, removal of them, or control of them developing again requires a stone restoration procedure, usually beyond the skill of a DIY type person.
While stone can be a gorgeous element in your home, proper care and periodic maintenance may be needed to keep them looking and performing to expectation.