The comparative absorption spectra of the asreceived ruby and surface treated ruby from 200 nm to 700 nm at room temperature are shown in Fig. 6. The typical absorption peaks at 264, 339,386, 553 and 700 nm (Fig. 6a) from the ruby after ACID treatment are observed. The peaks at 386 and 553 nm are basically the absorption from Cr3+in ruby. These two absorptions correspond to the optical transitions of4A2→4F1(U-band), 4A2→4F2,(Y-band), respectively [31]. The characteristic broad absorption peak at 700 nm corresponds to the R-line peak. This R-line absorption peak is the outcome optical transition of4A2→2E. In the ultraviolet region, there is a main absorption peak at 265 nm. This peak is associated with F+and F centers. When one or two electrons are captured by an oxygen vacancy, F and F+-centers formed[32]. Many more oxygen vacancies are produced by introducing Cr3+in to -Al2O3 lattice. Additionally, peaks at 373 and 742 nm Fig for the PbO treated sample and 415 nm for the ZnO treated samples are observed. The absorption peak at 373 and 742 nm for the PbO treated sample corresponds to the absorption peak of PbO2 whereas the peak at 415 nm for the ZnO treated sample corresponds to the absorption peak of ZnO.