Crystals
Beautiful formations
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. The scientific study of crystals
and crystal formation is known as crystallography. The process of
crystal formation via mechanisms of crystal growth is called
crystallization or solidification.
The word crystal derives from the Ancient Greek word κρύσταλλος
(krustallos), meaning both "ice" and "rock crystal",[3] from κρύος
(kruos), "icy cold, frost".