marcasite(redirected from marcasites)
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1. A mineral with the same composition as pyrite, FeS2, but differing in crystal structure. Also called white iron pyrites.
2. An ornament of pyrite, polished steel, or white metal.
[Middle English, from Medieval Latin marcasīta, from Arabic marqašīṯā, from Aramaic marqəšitā, from Akkadian marḫašu, from marḫaši, ancient region in the eastern Iranian plateau.]
mar′ca·sit′i·cal (-sĭt′ĭ-kəl) adj.
1. (Minerals) a metallic pale yellow mineral consisting of iron sulphide in orthorhombic crystalline form used in jewellery. Formula: FeS2
2. (Jewellery) a cut and polished form of steel or any white metal used for making jewellery
[C15: from Medieval Latin marcasīta, from Arabic marqashītā, perhaps from Persian]
1. a common mineral, iron sulfide, FeS2, chemically identical to pyrite but crystallizing in the orthorhombic system.
a. a crystallized form of this, used for jewelry.
b. any mineral resembling this form or any substance imitating it, esp. as used in jewelry.
[1375–1425; < Medieval Latin marcasīta < Arabic < Aramaic]
mar`ca•sit′i•cal (-ˈsɪt ɪ kəl) adj.