conchoidal
/kɑŋˈkɔɪdəl/
adjective
- Describing a type of fracture or surface that is curved and smooth, like the inside of a shell, especially in minerals or glass.
- When glass breaks, it sometimes shows a conchoidal shape.
- The geologist identified the rock by its conchoidal surface pattern.
- Obsidian often breaks with a conchoidal fracture, producing very sharp edges.