Lodestone

For a general description of the mineral itself, see Magnetite.
For other uses, see Lodestone (disambiguation).
Lodestone attracting some iron nails
Lodestone in the Hall of Gems of the Smithsonian
Lodestone attracting small bits of iron

Lodestones are naturally magnetized pieces of the mineral magnetite.[1][2] They are naturally occurring magnets, which can attract iron. The property of magnetism was first discovered in antiquity through lodestones.[3] Pieces of lodestone, suspended so they could turn, were the first magnetic compasses,[3][4][5][6] and their importance to early navigation is indicated by the name lodestone, which in Middle English means "course stone" or "leading stone",[7] from the now-obsolete meaning of lode as "journey, way".[8]

Lodestone is one of only a very few minerals that is found naturally magnetized.[1] Magnetite is black or brownish-black, with a metallic luster, a Mohs hardness of 5.5–6.5 and a black streak.

  1. ^ a b Hurlbut, Cornelius Searle; W. Edwin Sharp; Edward Salisbury Dana (1998). Dana's minerals and how to study them. John Wiley and Sons. pp. 96. ISBN 0-471-15677-9.
  2. ^ Bowles, J. F. W.; R. A. Howie; D. J. Vaughan; J. Zussman (2011). Rock-forming Minerals: Non-silicates: oxides, hydroxides and sulphides, Volume 5A, 2nd Ed. UK: Geological Society of London. p. 403. ISBN 978-1862393158.
  3. ^ a b Du Trémolet de Lacheisserie, Étienne; Damien Gignoux; Michel Schlenker (2005). Magnetism: Fundamentals. Springer. pp. 3–6. ISBN 0-387-22967-1.
  4. ^ Dill, J. Gregory (Jan–Feb 2003). "Lodestone and Needle: The rise of the magnetic compass". Ocean Navigator online. Navigator Publishing. Retrieved 2011-10-01.
  5. ^ Merrill, Ronald T.; Michael W. McElhinny; Phillip L. McFadden (1998). The Magnetic Field of the Earth. Academic Press. p. 3. ISBN 0-12-491246-X.
  6. ^ Needham, Joseph; Colin A. Ronan (1986). The Shorter Science and Civilization in China. UK: Cambridge Univ. Press. pp. 6, 18. ISBN 0-521-31560-3.
  7. ^ "Lodestone". Merriam-Webster online dictionary. Merriam-Webster, Inc. 2009. Retrieved 2009-06-12.
  8. ^ "lodestone". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.): 'Literally 'way-stone', from the use of the magnet in guiding mariners.'