Stuctures that resemble diamond in a broad sense, strong stiff structures containing dense, three dimensional networks of covalent bonds, formed chiefly from first and second row atoms with a valence of three or more. Many of the most useful diamondoid structures will in fact be rich in tetrahedrally coordinated carbon. Materials with superior strength to weight ratio, as much as 100 to 250 times as strong as Titanium, and much lighter. Possibly used to build stronger lighter rockets and space components, or a variety of other earth-bound articles for which weight and strength are a consideration.