Crystals are fascinating to people.
Crystals are an opportunity to apply math to real life objects.
Crystals make us ask questions. Finding the answers to some of the questions is the purpose of this unit. The unit discusses growing crystals, the history and theory of crystals, group theory, Miller indices, and mechanical drawing. The symmetries of the equilateral triangle and the square are developed. The symmetries of the square are used to solve a chess problem.