conchoidal fracture
Curved glassy breakage
Conchoidal fracture is the way certain materials break along smooth, curved surfaces rather than flat planes.
The resulting fracture pattern resembles the interior of a seashell—concentric ripples radiating from the point of impact.
Glass, obsidian, and flint break this way, which made them ideal for prehistoric toolmaking: The obsidian blade showed the conchoidal fracture typical of volcanic glass.
- obsidianGlassy igneous rock
- volcanic glassAmorphous ignite rock
- glassTransparent solid from sand
- breaking glassFracturing transparent material
- flintSpark-producing sedimentary rock
shell-like · curved · brittle · shatter · knapping · pressure flaking · stone tools · arrowhead · volcanic · quartz · chert · smooth · ripples · glassy · mineral · sharp · toolmaking · archaeology
- crystal propertieshardness, luster, cleavage, streak, specific gravity
- cleavagefour directions
conch, concha, fracture, fractured, fractures, fracturing, fraction, fractional, fractionally