Mineral Cleavage 2D — Crack-Front Propagation

This is the same cleavage physics as the 3D crystal-lattice model, seen from the side and re-derived with the mechanism that actually makes a mineral snap rather than crumble: a broken bond concentrates stress on its neighbours. A 2D grid of atoms stands in for a cross-section through halite, mica or quartz; pull it along X or Y and watch each bond resolve its share of the load, and — once the first bond in a line gives way — watch the classic Inglis stress-concentration formula from fracture mechanics take over, racing a crack front down that line far faster than uniform loading alone would predict. Compare halite's single clean split, mica's one-direction basal cleavage, and quartz's ragged multi-line conchoidal break to see how bonding anisotropy, not just bond strength, decides where and how a mineral fractures.