Marble dust

While many can see how important marble is for sculpture and other 3-dimensional art and architecture, it is somewhat surprising to hear that marble dust is useful.

Artists have used crushed marble for a long time. The finest grade has been used as inert pigment in early types of paint. The coarser grittier grades as aggregate.

Where it is really invaluable is in the context of frescos. Here marble (crystaline calcium carbonate) is used to mix into the plaster being used as a painting surface. The particles add sparkles to the surface and provide irridecence to the work of art. If you did not, the fresco might otherwise look dull.