Definitions for "Pietra dura"
Hard and fine stones in general, such as are used for inlay and the like, as distinguished from the softer stones used in building; thus, a Florentine mosaic is a familiar instance of work in pietra dura, though the ground may be soft marble.
inlaid mosaic of hard, semi-precious stones
From the Italian meaning "hard stone," an inlaying technique using various stones such as malachite, lapis lazuli, and jasper to create articles of jewelry and small decorative objects; usually associated with workshops in Florence.