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:

    What though the traveler tell us of the ruins of Egypt, are we so sick or idle that we must sacrifice our America and today to some man’s ill-remembered and indolent story? Carnac and Luxor are but names, or if their skeletons remain, still more desert sand and at length a wave of the Mediterranean Sea are needed to wash away the filth that attaches to their grandeur. Carnac! Carnac! here is Carnac for me. I behold the columns of a larger
    and purer temple.
    Henry David Thoreau (1817–1862)

    In a moment when criticism shows a singular dearth of direction every man has to be a law unto himself in matters of theatre, writing, and painting. While the American Mercury and the new Ford continue to spread a thin varnish of Ritz over the whole United States there is a certain virtue in being unfashionable.
    John Dos Passos (1896–1970)