Lodestone

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.

^ ^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.
^ 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.
^ ^a ^b Du Trémolet de Lacheisserie, Étienne; Damien Gignoux; Michel Schlenker (2005). Magnetism: Fundamentals. Springer. pp. 3–6. ISBN 0-387-22967-1.
^ Dill, J. Gregory (Jan–Feb 2003). "Lodestone and Needle: The rise of the magnetic compass". Ocean Navigator online. Navigator Publishing. Retrieved 2011-10-01.
^ 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.
^ 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.
^ "Lodestone". Merriam-Webster online dictionary. Merriam-Webster, Inc. 2009. Retrieved 2009-06-12.
^ "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.'

[Dana-1] 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.

[Bowles-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.

[Tremolet-3] 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.'

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