gems, gemology, advanced gemology, luminescence, cathodoluminescence, gem testing

The use of cathodorays is well known among physicists, dating back more than one century. But the use of cathodoluminescence (CL) as a means for gemstone recognition is not so well established among gemmologists of today. It was an Italian mineralogist, A. Pochettino, who, apparently, was the first to investigate the CL-effects in minerals, observing and measuring them as early as 1910. At about the same time the Austrian mineralogist, H. Michel, then keeper of the mineralogical department of the Austrian Museum for Natural History, also one of the first gemmologists of central Europe, began, by visual inspection of CL-colours, to differentiate between genuine and synthetic gemstones. Later on CL of gemstones, unfortunately, became a nearly forgotten or discredited method. Its renaissance in gemmology started when Gaal published his work in the seventies. Besides books by Marfunin and Lumb, information on CL of minerals is still sparse and papers are widely scattered among numerous periodicals. Practically nothing is published on CL of gemstones.