Blue stone is limestone, which contains small fossils (crinoids). Stone has almost zero porosity and permeability and is therefore an outstanding building stone. It has been used for more than 2000 years in Europe, The Romans used it all over Western Europe and Northern Italy. Walking and/ or driving on the stone will change the surface to darker blue tones. The character of the stone reflects the usage and uniqueness of this material. After more than 2,000 years still one the most demanded stone types.