gems, beryl, emerald, Colombia, Muzo, bibliography

Bergt describes the celebrated emerald mines of Muzo in Colombia, with particular attention to their geological setting and the mode of occurrence of the emeralds. He discusses the sedimentary rocks of the district and the veins and fissures in which emerald occurs, together with calcite and other associated minerals, and considers the geological processes responsible for the mineralization. The character of the emerald-bearing zones and their relationship to the surrounding rocks are described, as are the mining operations by which the deposits were exposed and worked. Bergt also comments on the occurrence and quality of the emerald crystals and on Muzo’s importance as a source of gem material. The paper forms part of his broader Geologische Studien in der Republik Colombia and provides a concise late nineteenth-century geological account of one of the world’s most historically important emerald deposits, emphasizing the geological relationships between the emerald mineralization, its associated minerals, and the enclosing sedimentary formations.