Book 27, Question 3
Why do crystals have flat sides and sharp corners?
Crystals grow outward by adding one layer of atoms at a time, and every layer follows the same pattern as the one under it.
The flat faces you see are the outer edges of those neat layers. The corners are where flat faces meet. When a crystal has room to grow without bumping into anything, those smooth faces and sharp points can look like they were cut by a jeweler.