Corundum of semi precious gem variety occurs within the hydrothermally altered metaultramafites in the retrograde metamorphic terrain of kannur district along the north eastern part of kerala. Samples of semi-translucent to opaque nature with red to crimson red colour are studied through advanced spectroscopic techniques namely FTIR, Raman, Photoluminescence, UV-Visible and SEM-EDAX. Spectroscopic studies coupled with Geochemical perspective indicates the presence of considerable concentration of Cr2+ accompanied by more or less equal amounts of Ti2+, V2+ and Ga2+, along with other ions. A gemmological appraisal is carried out correlating the presence Cr2+ content and the absence of much OH associated impurities in them. Distinctive absorbance peaks of corundum corresponding to the Fe as well as Cr chromophores and typical emittance peaks with a greater magnitude indicating the prominence of Cr chromophores in the samples as evident from its colour is observed from the UV-Visible and the Photoluminescence spectrum respectively. The FT-IR spectrum shows the absence of much hydroxylated ions and the Raman spectrum substantiates it with the explicit presence of the peaks corresponding to the Raman active vibrational modes in corundum, which resulted in the diaphenity of the samples positively.
