Desert Varnish

Desert varnish or rock varnish is an orange-yellow to black coating found on exposed rock surfaces in arid environments. Desert varnish is usually around one micron thick and present nanometre-scale layering. Rock rust and desert patina are other terms which are also used for the condition, but less often.

Read more about Desert Varnish:  Formation, Composition

Famous quotes containing the words desert and/or varnish:

    I may be able to spot arrowheads on the desert but a refrigerator is a jungle in which I am easily lost. My wife, however, will unerringly point out that the cheese or the leftover roast is hiding right in front of my eyes. Hundreds of such experiences convince me that men and women often inhabit quite different visual worlds. These are differences which cannot be attributed to variations in visual acuity. Man and women simply have learned to use their eyes in very different ways.
    Edward T. Hall (b. 1914)

    People are less self-conscious in the intimacy of family life and during the anxiety of a great sorrow. The dazzling varnish of an extreme politeness is then less in evidence, and the true qualities of the heart regain their proper proportions.
    Stendhal [Marie Henri Beyle] (1783–1842)