1) The building block of all silicates. It is composed of one silicon atom equidimensionally placed around four oxygen atoms. The groups of silicates are classified based on how the tetrahedrons join together.2) Four sided polyhedron which has all sides equidimensional and triangular shaped. Minerals shaped as tetrahedrons belong to the isometric system. Plural of Tetrahedron is Tetrahedra or Tetrahedrons.
