17th International Gemmological Conference was held on September 23-27, 1979 at Diamant und Edelsteinborse, Idar-Oberstein, Germany. There were about 40 participants from 16 countries, and 30 papers were presented. These papers are abstracted. Field excursions to old agate mine and places of geological interests, as well as visits to gem minerals collections were organized. It was officially decided that the next conference be held in Japan in 1981.
