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出典:Wiktionary
出典:『Wiktionary』 (2024/09/26 19:22 UTC 版)
From Ancient Greek χιαστός (khiastós, “arranged diagonally”) derived from χι (khi, “Greek letter X khi”) + -lite. So called from the resemblance of the crosscuts of its crystals to the Greek letter chi.
chiastolite (countable and uncountable, plural chiastolites)
出典:Wikipedia
出典:『Wikipedia』 (2011/07/05 23:26 UTC 版)
The mineral chiastolite is a variety of andalusite with the chemical composition Al2SiO5. It is noted for distinctive cross-shaped black inclusions of graphite. In areas around Georgetown, California, metamorphosed sediments contained andalusite and chiastolite in a graphite rich metasediment. The chiastolite crystals have been pseudomorphically altered by a mixture of muscovite, paragonite and margarite. The calcium rich margarite tends to form along the graphite rich crosses or bands within the chiastolite. Mineralogically the occurrence is important because all three white mica phases are present in an equilibrium assemblage.