I. Introduction - What is a crystal? A crystal by definition is a solid whose atoms, ions or molecules are arranged in a regular and repeating pattern. These magnificent solids are formed when they undergo a process called nucleation. Nucleation is the process that occurs in the formation of a crystal. The ions, atoms or molecules of the solution, liquid or vapor (depending on which crystal it grows in) arrange themselves in a pattern that has the characteristics of a crystalline solid. This pattern forms the site where additional particles remaining will be deposited as the crystal grows. The structure of a crystal is made up of matter formed by an ordered arrangement of atoms, molecules or ions. The structure is made up of repeating units that give the structure recognizable characteristics.II. Lattice systems and chemical propertiesCrystal structures are divided into seven systems called lattices. A lattice is the arrangement of points where the atoms, ions or molecules that make up a crystal are centered. The seven crystals of the system are divided into cubic, tetragonal, orthorhombic, hexagonal, trigonal, triclinic and monoclinic. The cubic system is quite basic. It consists of one lattice point at each corner of the cube, which each lattice point shares equally among eight adjacent cubes. The tetragonal system is similar to cubic crystals, but is longer along one axis. Tetragonal crystal lattices form when stretching along a lattice vector has occurred. As a result, the cube is transformed into a rectangular prism with a square base. The orthorhombic system is like tetragonal crystals, but does not have a square in the cross section. This lattice is formed when stretching has occurred along two lattice vectors, which are formed at the center of the paper through the diamonds.V. Everyday Uses of Crystals We may not realize it, but we encounter crystals every day. Many of us look at a watch face several times a day. The glass covering the face of the watch is actually made of crystals! Many of us also come across LCD (liquid crystal display) displays on a daily basis. Liquid crystal displays (LCD) include mobile phone screens, monitor screens, and portable gaming device screens. We don't just use crystals on a daily basis for entertainment, we can consume them too! Table salt (NaCL) is a crystalline compound as is sucrose (table sugar) and even chewing gum! Crystals can also help maintain good hygiene. Crystals are found in toothpaste! Crystals play a very important role in our life. They have helped our society evolve scientifically into what it is today.