Silica formed on the surface of Cool White phosphor by precipitation of either tetraethylorthosilicate or Ludox AM (aqueous colloidal silica) is not homogenously distributed. Electron spectroscopy for chemical analysis indicates that oxygen sites of the phosphor surface are preferentially coated. The preference for oxygen sites is likely the result of hydrogen bonding formation available at these sites. There was no preference for the remaining sites (Ca, F, and P) which are probably adsorbed by physisorption.