Conservation of Rock Art. Proceedings of the International Workshop on the Conservation of Rock Art, Perth, September 1977 (1978), pp. 32-35
Nature of silcrete skin: silcrete skin on sandstone is defined as a superficial orthoquartzite that is coated with a mixture of cryptocrystalline to amorphous silica with some oxides of iron. Manganese and titanium in varied amounts. Its formation is a function of rainfall.