Bologna, Italy/bologna020
Previous | Home | NextInside the museum, the original "fosforo di Bologna." This is an unusual form of barium sulfate, crystallized in the form of a geode resembling a fossilized ammonite. During the first decade of the 1600s, a cobbler named Vincenzo Casciarolo discovered this stone stone in nearby hills which became phosphorescent when heated. This material became known as the “glowing stone of Bologna” or “phosphoro di Bologna.” The active phosphorescent form is actually barium sulfide, reduced from the original barium sulfate. Recent studies by Italian chemists have tried to duplicate the original recipe, and it appears that an admixed metal is necessary and probably was one of the secret ingredients of the original recipe.
