By the chemical, magnetic and X-ray-analysis, the production of Ni(OH)2-monolayer-microclusters was identified in the precipitates from the mixing of aqueous solutions of NiCl2.6H2O and Na2SiO3.nH2O (n=0 or 9). The magnetic transition temperature of 10.2K was discussed, based on the finite size effect in the magnetic microcluster.