Definition of marcasite in English:

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Pronunciation: /ˈmɑːkəsʌɪt/
Pronunciation: /ˈmɑːkəziːt/


1A semi-precious stone consisting of iron pyrites.
Example sentences
  • Access to the pit is prohibited, but excellent specimens of calcite scalenohedra, dolomite rhombohedra, pyrite, and marcasite have been collected from the pit's east wall.
  • Two small dumps are exposed, affording an opportunity to collect some of the attractive microcrystals of rhodochrosite and crystals of apatite, gypsum, barite, goethite, marcasite, calcite, and chalcocite that are found there.
  • Other minerals mentioned from the mine by Dunham include galena, sphalerite, pyrite, chalcedony, and minor marcasite and pyrrhotite.
1.1 [mass noun] A bronze-yellow mineral consisting of iron disulphide but differing from pyrite in typically forming aggregates of tabular crystals.
Example sentences
  • The bodies of iron sulfide nodules in the Olentangy Shale are composed of fine-grained pyrite, and their surfaces are frequently covered with tabular crystals of marcasite.
  • Sphalerite stalactites to 15 cm in diameter and coated with crystallized marcasite and galena are reported from the Marsden prospect near Galena, Illinois.
  • We have also noted clumps of small marcasite crystals as a late-stage association with galena and drusy quartz from the Eagle mine.
1.2A piece of polished steel or a similar metal cut as a gem.


Late Middle English: from medieval Latin marcasita, from Arabic marqašīṯa, from Persian.

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Line breaks: mar¦cas|ite

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