a type of atomic orbital hybridization. If one mathematically manipulates the s orbital and three p orbitals, one can produce a hybrid of the orbitals that have some of the characteristics of one and some of the characteristics of the other. Nature seems to like to do this, since the sp3-hybridized form of crystallized carbon, commonly called diamond, is the hardest substance known to naturally occur. Diamond owes its hardness to the strength and stability of tetrahedrally bonded carbon atoms.