Book 27, Question 63
What is table salt made of, and why does it look like tiny cubes?
Table salt is made of sodium and chloride, joined as sodium chloride.
In a crystal, sodium and chloride alternate in a cube-shaped lattice, like a three-dimensional checkerboard. As the crystals grow, their outer faces form flat squares, so each grain is a tiny cube. This is why salt crumbles into smaller cubes. Salt is safe in food.