The natural ruby stones, varying in size between 5 and 13 mm,were collected from Nuapada district of Odisha. These gemstones mostly appear hexagonal though irregular stones are not uncommon (Fig. 1). These natural ruby stones were surface cleaned with acetone, dilute HCl and subsequently by ACID to remove the inter-face and inherent impurities present in them. The alumina crucible containing ruby covered with PbO powder was loaded in to a resistance-heated (Relek Pvt. Ltd. and Model No TQ1164) muffle furnace. The sample was then heated in open atmosphere up to 500◦C with a heating rate of 10◦C/min. After 500◦C the system was ramped up to 1200◦C in the same atmosphere with a heating rate of 8◦C/min. Thereafter, the system was kept for 2 h in 1200◦C in the same atmosphere. Finally, the reactor temperature was turned off and the system was cooled to room temperature.Similar procedure was also adopted for the ZnO treatment. Subsequently, after heat treatment, the ruby stones are cleaned with dilute HCl (50% dilute) for 1 h followed by ultrasonication in ace-tone bath for 10 min. The PbO and ZnO powders were purchased from the Alfa Aesar company with a purity of 99.99% (metals basis).