Marble chips that have been crushed to form a powder. Marble dust is used as an inert pigment and filler in paints. Even as a fine powder, some of the crystalline surfaces reflect light adding a sparkle to regions in which it has been added to the plaster used in a fresco support. Synonyms: marble meal; marble grit. Museum of Fine Arts, Boston (2000). [J. Cassar, R. de Angelis]