It was shown, that using of sodium metasilicate (Na2SiO3) as stabilizing agent for CdS quantum dots or Ag nanoparticles in water leads to the formation of stable colloids of CdS/SiO32- and Ag/SiO32- particles. These colloids are active in the visible range of the spectrum. According to TEM and UV-visible spectroscopy data, an average size of the particles in colloids was ∼ 5 nm for CdS and 2-10 nm for Ag. Ag/SiO32- water colloids showed an absorption band with a maximum at 380-410 nm. This band belonged to surface plasmon resonance. CdS/SiO32- water dispersions were characterized by luminescence at the region of 500-800 nm. The luminescence intensity increased after addition of Ag+ into the colloids of CdS/SiO32-.