The growth of inorganic particles with chemical zoning is studied with the reaction-diffusion in gel. The two kinds of cations Ca 2 and Mg 2 diffuse into a gel, and a reactive anion CO 2 3 diffuses from the opposite side. The distinct chemical zoning was generated in the particles formed in the agar and in the restricted concentration range of the electrolytes in the reservoir. No chemical zoning is observed in gelatin. The particle structure is significantly affected by the gel type especially in the early stage of the growth. These characteristics can be understood taking into account the difference in the diffusion rates of the two kinds of cations. When several kinds of cation pairs are used, there is a pair that forms a novel stripe pattern of the precipitates. The pattern is also controlled by the difference in the diffusion rates of two kinds of cations.

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