Natural brick-and-mortar composite of aragonite platelets in an organic matrix lining mollusc shells.
Core Principles & Analysis
Although about 95% brittle aragonite by weight, nacre's work of fracture is up to 3,000 times that of the pure mineral.
Aragonite 'bricks' roughly half a micrometre thick are mortared by nanometre-scale layers of chitin and proteins, and platelet sliding dissipates crack energy.
Its architecture inspires engineered 'nacre-like' materials, including freeze-cast ceramics and laminated glass that fail gracefully instead of shattering.