Ear piercing is one of the oldest known forms of body modification, with artistic and written references from cultures around the world dating back to early history. Early evidence of earrings worn by men can be seen in archeological evidence from Persepolis in ancient Persia. The carved images of soldiers of the Persian Empire, displayed on some of the surviving walls of the palace, show them wearing an earring. A crystal or crystalline solid is a solid material whose constituents, such as atoms, molecules or ions, are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macroscopic single crystals are usually identifiable by their geometrical shape, consisting of flat faces with specific, characteristic orientations.
