Chabazite-Na crystals from Aci Castello, Sicily, Italy, Gerd Tremmel collection – small cabinet specimen as unique piece
This small cabinet specimen shows Chabazite-Na crystals from Aci Castello, Sicily, Italy, from the Gerd Tremmel collection. Colorless to white Chabazite-Na crystals with vitreous luster are developed in a cavity within the dark volcanic matrix. The crystals are clearly formed and display typical rhombohedral shapes that contrast strongly with the basaltic groundmass. Some crystal faces are transparent to translucent and reflect light vividly. The combination of dark host rock and bright crystals gives the specimen a balanced and aesthetic overall appearance.
Geology & Origin
Chabazite-Na belongs to the zeolite group and forms secondarily in cavities of volcanic rocks. In the basalts of Sicily it develops through hydrothermal processes when sodium rich solutions penetrate gas bubbles and fractures and crystallize there. Aci Castello is a classic locality for zeolites in basaltic rocks of the Mount Etna volcanic field. The crystals shown here illustrate the typical formation of zeolites in vesicular lavas under post volcanic conditions.