Hardstone

Hardstone is an unscientific term, mostly encountered in the decorative arts or archaeology, that has a similar meaning to semi-precious stones, or gemstones. Very hard building stones, such as granite, are not included in the term in this sense; only stones which are fairly hard, and regarded as attractive - in effect ones which could be used in jewellery. Hardstone carving is the three-dimensional carving for artistic purposes of semi-precious stones such as jade, agate, onyx, rock crystal, sard or carnelian, and a general term for an object made in this way. Two-dimensional inlay techniques for floors, furniture and walls include pietre dure, opus sectile (Ancient Roman), and medieval Cosmatesque work - these typically inlay hardstone pieces into a background of marble or some other building stone.