gems, agate, Germany, Idar-Oberstein, history lapidary, fashioning

A richly illustrated special issue devoted to agate, with particular emphasis on the geological, historical and lapidary traditions of Idar-Oberstein and the surrounding Saar–Nahe region. It examines the occurrence and formation of agates, geodes and related silica varieties, including the mineralogy and geology of the historic Steinkaulenberg deposits, and discusses theories of agate genesis and silica deposition. Historical contributions trace the exploitation of local agate and jasper, the development of mining and cutting at Idar-Oberstein, and the importance of imported rough once local supplies declined. The volume also surveys notable agate occurrences and characteristic material from other localities, combining geological descriptions with numerous photographs of specimens. Overall, it presents agate both as a mineralogical phenomenon and as the gemstone around which the Idar-Oberstein cutting industry developed.