The surface of crystals often have regions that are flat, called facets. Facets occur naturally as crystals form, because flat layers of atoms are usually the most stable. The atoms in a facet are arranged in a regular pattern, such as the pattern of a chess board or a honeycomb. These facets reflect light to give crystals their shiny or sparky appearance. Artificial facets can be made in any shape by cutting or grinding a crystal, which is how some gemstones for jewelry are made. 