The Collaborative International Dictionary of English v.0.48:

Loadstone \Load"stone`\, Lodestone \Lode"stone\, n. [Load, lode
   + stone.] (Min.)
   A piece of magnetite, a magnetic iron ore, possessing
   polarity like a magnetic needle, having the power to attract
   as well as to be attracted magnetically. See Magnetite.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lodestone \Lode"stone`\, n. (Min.)
   Same as Loadstone.
   [1913 Webster]

WordNet (r) 3.0 (2006):

lodestone
    n 1: a permanent magnet consisting of magnetite that possess
         polarity and has the power to attract as well as to be
         attracted magnetically [syn: lodestone, loadstone]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "lodestone":
   ambition, artificial magnet, bar magnet, catch, dearest wish,
   desideration, desideratum, desire, electromagnetic lifting magnet,
   field magnet, forbidden fruit, glimmering goal, golden vision,
   hope, horseshoe magnet, lodestar, magnet, magnetic needle,
   magnetite, paramagnet, plum, polestar, prize, solenoid, temptation,
   trophy, wish