Jasper rock is a variety of chalcedony, also known as chert, an impure variety of silica (SiO2). It is opaque and occurs in many different colours. When referred to as picture jasper, dendrites, banding patterns and colour variation result in suggestive scenery, like the landscape here depicted in a polished slice. Actual width is 100 mm and provenance of this specimen is the Kalahari Desert of Namibia. Among mineral traders it is also known as Kalahari Picture Jasper.