出典:Wiktionary
From Medieval Latin marchasita et al., from Arabic مَرْقَشِيتَا (marqašītā).
marcasite (countable かつ uncountable, 複数形 marcasites)
出典:Wikipedia
出典:『Wikipedia』 (2011/06/14 12:49 UTC 版)
The mineral marcasite, sometimes called white iron pyrite, is iron sulfide (FeS2) with orthorhombic crystal structure. It is physically and crystallographically distinct from pyrite, which is iron sulfide with cubic crystal structure. Both structures do have in common that they contain the disulfide S22- ion with a short, bonding distance between the sulfur atoms. The structures differ in how these dianions are arranged around the Fe2+ cations. Marcasite is lighter and more brittle than pyrite. Specimens of marcasite often crumble and break up due to the unstable crystal structure.