noun
chert
Rare mineralogical term for chert, a hard, fine-grained sedimentary rock composed of microcrystalline quartz. Often encountered in geological contexts; the loanword チャート is more common in modern Japanese.
See also: チャート
この地層には角岩が多く含まれている。
This stratum contains a lot of chert.
角岩は非
Chert is a very hard rock and was also used as a material for stone tools.