馬ば蹄てい石せき

noun

obsidian

A mineralogical term for obsidian, a dark volcanic glass. The kanji literally mean 'horseshoe stone', possibly from its appearance or historical use.

• 馬ば蹄てい石せきは火か山ざんガラスの一いっ種しゅで、黒こく曜よう石せきとも呼よばれる。

  Bateiseki is a type of volcanic glass, also called kokuyouseki (obsidian).