The smallest portion of a crystal which contains all the fundamental properties and acquires the structure of a crystal, without any repetition is called the unit cell of crystal.
By joining several unit cells in three dimensional space the crystal is formed. Unit cells or the crystal has the following seven types of geometrical shapes:
- Cubic;
- Tetragonal;
- Orthorhombic;
- Monoclinic;
- Triclinic;
- Rhombohedral;
- Hexagonal
