WordNet (r) 3.0 (2006):

precious stone
    n 1: a precious or semiprecious stone incorporated into a piece
         of jewelry [syn: jewel, gem, precious stone]

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "precious stone":
   anklet, armlet, bangle, beads, bijou, bracelet, breastpin, brooch,
   chain, chaplet, charm, chatelaine, circle, coronet, crown, crystal,
   diadem, earring, fob, gem, gem stone, jewel, locket, necklace,
   nose ring, pin, rhinestone, ring, semiprecious stone, stickpin,
   stone, tiara, torque, wampum, wristband, wristlet