Glass is a super cooled liquid and an amorphous substance. Quartz is the crystalline form of silica (SiO2) ‘n which tetrahedral units SiO4 are linked with each other in such a way that the oxygen atom of one tetrahedron is shared with another Si atom. Quartz cap be converted into glass by melting it and cooling the melt very rapidly. In glass, SiO4 tetrahedra are joined in a random manner.