An interesting greenish blue cabochon of chalcedony was examined to determine the identity of some peculiar yellowish green inclusions. The bodycolor offered some clues, as the greenish blue variety of chalcedony, known as “gem silica,” is commonly attributed to the copper mineral chrysocolla. Therefore, it was not a surprise when Raman spectrometry identified the yellowish green inclusions as another mineral that contained a significant amount of copper: conichalcite (see above).
Conichalcite, CaCu(AsO4)(OH), is a member of the adelite-descloizite group and occurs in colors from dominantly green to dominantly yellow, with either a yellow or green modifier. Conichalcite is reported to occur with chrysocolla from deposits in the United States (Utah, Arizona, and California), Germany, Peru, and Australia. This particular gem was reportedly from Concepcion Del Oro, Zacatecas, Mexico.
These vibrant inclusions were quite visually striking when seen along with their greenish blue host chalcedony. This is the first time the authors have identified inclusions of conichalcite in chalcedony.
An interesting greenish blue cabochon of chalcedony was examined to determine the identity of some peculiar yellowish green inclusions. The bodycolor offered some clues, as the greenish blue variety of chalcedony, known as “gem silica,” is commonly attributed to the copper mineral chrysocolla. Therefore, it was not a surprise when Raman spectrometry identified the yellowish green inclusions as another mineral that contained a significant amount of copper: conichalcite (see above).
Conichalcite, CaCu(AsO4)(OH), is a member of the adelite-descloizite group and occurs in colors from dominantly green to dominantly yellow, with either a yellow or green modifier. Conichalcite is reported to occur with chrysocolla from deposits in the United States (Utah, Arizona, and California), Germany, Peru, and Australia. This particular gem was reportedly from Concepcion Del Oro, Zacatecas, Mexico.
These vibrant inclusions were quite visually striking when seen along with their greenish blue host chalcedony. This is the first time the authors have identified inclusions of conichalcite in chalcedony.
