scene with fish and shells, semi-precious stones including malachite, marble and more, image area 2" X 4 1/2" plus mat and frame.....pietra dura, (Italian: “hard stone”), in mosaic, any of several kinds of hard stone used in commesso mosaic work, an art that flourished in Florence particularly in the late 16th and 17th centuries and involved the fashioning of highly illusionistic pictures out of cut-to-shape pieces of coloured stone.