Zinc ion implanted silica with controlled thermal treatments and pulsed laser radiation has been investigated. Optical spectra of the as-implanted silica at higher doses (>3 X 10(16) ions/cm(2)) and/or the samples annealed in a reducing atmosphere show both Zn clusters and Zn metal colloid formation. The absorption peak at similar to 5.3 eV is attributed to the surface plasmon absorption of Zn metal colloids in silica. The oxidized samples with the ion dose greater than or equal to 3x10(16) ions/cm(2) show an absorption peak in 4.3-4.7 eV region implying ZnO quantum dot formation. It is expected that the average size of the ZnO nanoparticles becomes smaller for lower ion dose. Therefore, a blueshift of the absorption peak with lower ion dose can be attributed to the quantum confinement effects. Pulsed laser radiation at 266 nm with energy density of 30 mJ/cm(2) causes a brownish coloration in these optically transparent Zn implanted silica substrates. The color formation is an irreversible process. Therefore, it is believed that new chemical species may have formed through photochemical reactions. The results also show that the coloring process is photon energy dependent.