Involves sharing of all basal oxygens to form a sheet of silicate tetrahedra. On top of this layer is a layer of cations, then another sheet of silicates, etc. etc. This gives the well developed basal cleavage in this group. Common sheet silicates are the micas. All four oxygens are shared to build up a framework of tetrahedra.
Good example is quartz.
Oxides - Consist of oxygen plus a cation, often Fe, Ti, Al, Cu, or Cr. Major source of world s iron, aluminum and chromium. Sulfides - Sulfur plus a metallic cation. Most of our important ore minerals are in this group. Another important group of ore minerals.