Rock candy is produced through controlled crystallization of a supersaturated sucrose solution, a process structurally identical to the formation of many evaporite minerals. A seed crystal (or granulated sugar surface) provides nucleation points; temperature manipulation drives crystal growth over six to seven days. The resulting specimens show excellent transparency, angular cleavage-like faces, and a satisfying heft. Unlike most ARE specimens, field testing is encouraged and delicious. Rock candy demonstrates crystallographic principles — nucleation, supersaturation, and crystal habit — in an immediately edible format. Note: specimens exhibit extreme solubility in water and in children. Store in a dry, childproof location.
Why sucrose belongs in the library
Sucrose crystallizes in the monoclinic system and grows by exactly the mechanism the field guides describe for hydrothermal minerals: a supersaturated solution, a seed surface, and patience. A jar of rock candy is the only crystal-growth experiment members can run on a kitchen counter and then eat — under the allergen standard's supervision, of course.