schist

...general term for crystalline metamorphic rocks with a thin, easily peeling structure (schistosity). Schistosity is a structure in which thin, plate-like minerals such as micas and chlorite, and columnar minerals such as amphibole and epidote are arranged parallel to a certain plane. The term schist is also commonly used in the name of metamorphic rocks, with the same meaning as crystalline schist. For example, if the main components of a metamorphic rock are quartz and muscovite, it is called quartz-muscovite schist. Also, based on the original chemical composition of the metamorphic rock, for example, a mudstone-type metamorphic rock is called pelitic schist.

*Some of the terminology that mentions "schist" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…薄くはがれやすい構造(片状組織，片理)をもつ結晶質の変成岩の総称。片状組織とは，雲母類や緑泥岩などの薄く板状の鉱物，角セン石や緑レン石などの柱状の鉱物が一定の面に平行に並んだものである。片岩schistという用語も結晶片岩と同じ意味で変成岩の岩石名に普通に用いられる。例えば，変成岩の主成分鉱物が石英と白雲母であれば石英‐白雲母片岩と，また，変成岩の元来の化学組成上の性質を参考にして，例えば泥岩質の変成岩ならば泥質片岩pelitic schistというようによばれる。…

※「schist」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報