method of cutting gemstones with a convex, rounded surface that is polished but unfaceted. Opaque, asteriated, iridescent, opalescent, or chatoyant stones are usually cut en cabochon. The back of a normal cabochon-cut stone is flat, but it may be hollowed to lighten the colour. Garnet, jasper, bloodstone, moonstone, cat's-eye, and star ruby and sapphire are among the gemstones usually finished in this manner.