What is Desert Varnish?
Desert Varnish, also known as rock varnish, desert patina, or rock rust, is the
popular term used to describe the naturally-occurring coating found on exposed
rock surfaces in arid climates throughout the world. Desert varnish can range
in color from various shades of brown to grey or black, depending on the ratio
of elements found in the varnish. Iron oxide, for example, is responsible for
the brownish-red coloring while manganese oxide creates the various shades of
grey and black. Many other factors such as hardness, water permeability,
precipitation, and pH levels, contribute to the creation of desert varnish.
