Water glass (Na2SiO3 concn. 5%) with varying silicate modulus (1.67-3.3) was used for pptn. of CuO center dot SiO2 composites from aq. soln. of Cu(NO3)(2) at 20 degrees C. The composite was dried at 105 C for 2 h and studied for chem. compn., particle size distribution (polydispersity index), surface morphol., wettability (H2O), pore size, N-2 adsorption capacity and lightness, color contribution, satn. and hue. The increase in the SiO2 modulus of water glass resulted in an increase of SiO2 content, wettability and N-2 adsorption of the composite material.