Lapidary is the practice of shaping stone, minerals, or gemstones into decorative items such as cabochons, engraved and faceted gems, using techniques such as cutting, grinding, and polishing. Another specialized form of lapidary work is the inlaying of marble and gemstones into a marble matrix. This technique is known as pietra dura, for the hardstones that are used, like onyx, jasper and carnelian. In Florence and Naples, where the technique was developed in the 16th century, it is called opere di commessi. The Medici Chapel at San Lorenzo in Florence is completely veneered with inlaid hard stones. In China, lapidary work specializing in jade carving has been continuous since at least the Shang dynasty.