Q.Name any two man-made silicates.

All silicate minerals — feldspar, mica, asbestos, zeolites and many others — are built from one repeating structural unit, the tetrahedral $SiO_4^{4-}$ anion, in which a central silicon is bonded to four oxygen atoms. Depending on the mineral, this basic tetrahedron either exists as an isolated, discrete ion, or many tetrahedra link together by sharing 1, 2, 3 or 4 of their oxygen corners with neighbouring units — sharing progressively more corners builds up chain silicates, ring silicates, sheet silicates, and, when every corner of every tetrahedron is shared, fully three-dimensional network silicates (such as the feldspars and zeolites). Whatever the resulting architecture, the silicate framework carries a net negative c …