The contribution of the rare elements in the determination of the origin of volcanic glass is examined in this paper. The chemical composition (Major, trace, and rare earth elements) of Trachilas perlite deposit is studied. Trachilas area is part of miles island, Aegean sea. Trachilas perlite belongs to the calc-alkaline series of the active Aegean volcanic arc. Perlite is the latest volcanic product, having arhyolitic composition. The main chemical variation between Trachilas and the other Greek pelrites are present in alkalies, Ba, Sr, Rb, and the R.E.E. The differences on the chemical composition indicate individual parent magmas which produced the various perlites.