Petit Granit, also known as Belgian Blue Stone or Pierre Bleue, is a prestigious crinoidal limestone quarried exclusively in the Wallonia region of Belgium. Characterized by its dense structure and deep blue-grey to charcoal-black tonality, it features a unique scattering of fossilized encrinite fragments that glisten like stars. Despite its name, which translates to Little Granite, it is a sedimentary rock whose durability and low water absorption have made it a staple of European architecture since the Middle Ages. Interestingly, while it appears deep black when polished, it transitions to a soft grey-blue when honed or aged outdoors.