Is there such a thing as a bacterium that eats stone?
Yes, a genus called Thiobacillus is responsible, and one microbe in that family has the ability to convert sulfur dioxide gas (found in the air) into sulfuric acid. The microbe then uses the acid to transform marble into calcium sulfate, better known as plaster. It can attack marble statues, tombs, monuments, and historic buildings, to name just a few objects. In recent years, public concern has arisen because historical monuments have shown a marked increase in such destruction. Automotive and industrial emissions put free sulfur dioxide gas into the atmosphere, and these bacteria take advantage of it.