[AS.] A piece of rock, or the hard centre of fleshy fruits. Building stones are natural or artificial. Natural stones are chiefly granite, marble, limestones, sandstones, and also slates. The hard stones are generally got by blasting, others by channeling and wedging, while the more fragile are sawn out in the quarries. Large masses of stone are called rock, smaller pieces stone, and finer pieces gravel, or still finer grains of sand. Precious stones include diamonds (q.v.), emeralds and beryls, sapphires (q. v.), and rubies (q. v.), amethysts, serpentine, malachite (q. v.), turquoise, jasper, jade, and chalcedony.