Jasper, SiO2 (Silicon Dioxide), is an example of cryptocrystalline quartz, a variety whose crystals are so minute they can only be seen through the microscope. It is formed from silica that has been removed from silicate minerals and then carried by water as ultrafine particles in colloidal suspension. It then settles out as a noncrystalline silica gel. The name Jasper is used for highly coloured varieties.

Description:  This specimen is referred to as Leopard Skin because of the particulalry striking pattern. It consists of alternating areas of pale and dark green colouration that resemble the skin of a leopard, albeit the pattern, not the colour. The mottled effect is very unusual and beautiful, especially in good light and when polished.

Location: Great Dyke, Zimbabwe.