Coordination polyhedra are geometric representations of how a cation is surrounded by an anion. In mineralogy, coordination polyhedra are often thought of with regard to oxygen, thanks its abundance from the crust. The bottom unit of silicate minerals is definitely the silica tetrahedron – one particular Si4+ surrounded by four O2−. https://beckettttuog.onesmablog.com/how-minerals-can-save-you-time-stress-and-money-70401703