貝かい殻がら状じょう断だん口こう

noun

conchoidal fracture

Technical term in geology and materials science for a curved, shell-like fracture surface, typical of glass and some minerals.

• 黒こく曜よう石せきは貝かい殻がら状じょう断だん口こうを示しめす。

  Obsidian exhibits a conchoidal fracture.