A natural mineral imported from Bologna, Italy composed of monoclinic prismatic crystals of hydrated calcium sulfate-carbonate. This is a finely-ground whiting that combines the advantages of both chalk (calcium carbonate) and gypsum (calcium sulfate) for making painting and gilding grounds that are brilliant white.

Use this whiting to make a gesso base for gilding that is easier to polish, yet mechanically strong. Use Bologna chalk in painting grounds that make a compact, durable surface for egg and casein tempera, distemper, encaustic, and oil paint.

Add this filler to oil colors and mediums to create textural and bodying qualities to oil paint without affecting the color.