Each of the model systems (carbonates, phosphates and oxalates of calcium, magnesium ammonium phosphates, layered double hydroxides – LDH) that is supposed to be studied can precipitate in the form of polymorphs, hydrates or chemically different compounds. Apart from their inherent aptness for the pure academic studies, these systems are also of practical importance because of their potential application. It is to be expected that the results of proposed investigations of calcium carbonate interactions with natural acid glycoproteins and synthetic analogues (acid poly-amino acids) will contribute to the development of new preparation method of composite biomaterials with exceptional mechanical properties. Likewise, the studies of porous calcium carbonate, hydroxyapatite and LDH, into which different classes of model organic molecules (polysaccharides, polypeptides, nucleic acids) are absorbed, will contribute to the development of organic/inorganic systems for a controlled release of active molecules in body. Besides, cognition on the conditions at which precipitation and transformation of calcium oxalates and magnesium (ammonium) phosphates take place (constituents of urinary calculi), will be a theorethical base and supplement to the clinical and epidemiological studies.