Pietra dura or pietre dure, called parchin kari in South Asia, is a term for the inlay technique of using cut and fitted, highly polished colored stones to create images. It is considered a decorative art. The stonework, after the work is assembled loosely, is glued stone-by-stone to a substrate after having previously been "sliced and cut in different shape sections; and then assembled together so precisely that the contact between each section was practically invisible". Stability was achieved by grooving the undersides of the stones so that they interlocked, rather like a jigsaw puzzle, with everything held tautly in place by an encircling 'frame'. Many different colored stones, particularly Marbles, Granite, Jasper, Jade, Onyx, Lapis, Lazuli, Chalcedony, Dyumorterit, Rhodusite, Rhodonite were used. It first appeared in Rome in the 16th century, reaching its full maturity in Florence. Typically the resulting panel is completely flat, but some examples where the image is in low relief were made, taking the work more into the area of hard-stone carving.
Pietre dure is an Italian plural meaning "hard rocks" or hard-stones; the singular pietra dura is also encountered in Italian. In Italian, but not in English, the term embraces all gem engraving and hard-stone carving, which is the artistic carving of three-dimensional objects in semi-precious stone, normally from a single piece, for example in Chinese jade. The traditional convention in English has been to use the singular pietra dura just to denote multi-colored inlay work. The English term "Florentine mosaic" is sometimes also encountered, probably developed by the tourist industry. Giovanni Montelatici (1864-1930) was an Italian Florentine artist whose brilliant work has been distributed across the world by tourists and collectors.
It is distinct from mosaic in that the component stones are mostly much larger and cut to a shape suiting their place in the image, not all of roughly equal size and shape as in mosaic. In pietra dura, the stones are not cemented together with grout, and works in pietra dura are often portable.