Abstract12-Amino-acid peptides with binding-selected sequences and random functional groups synthesize the same inorganic material. Bacteria use structured polymers as filaments of cytoskeletal protein and of polysaccharides in templating biominerals. Nucleation appears to be involved not only in crystal formation, but also in the formation of porous or amorphous inorganic material. A seed of one iron ion for an iron-oxide cluster could be obtained in the low-iron-state of an archeal ferritin crystal. Porous inorganic materials were described to grow out in huge channeled complexes of organic compounds or crystallized seawater. The evolutionary progress of biomineralization runs apparently in the development of complex, inorganic-organic hybrid materials, composites, which are often structured hierarchically. The mechanical properties of a mineral undergo a change by presence and partition of the organic material, the most prominent example being the human skeleton. In order to describe such a complex system, a mathematical procedure -the finite element analysis -was introduced with great success. This analysis is governed amazingly by only one physical quantity, force, together with the modulus of elasticity. The overwhelming extent of research into the mechanical properties of skeletons has resulted in the conclusion that the aim of biomineralization appears to be stability.