Definition of desert varnish in English:

desert varnish

noun

Geology
  • A dark, hard film of oxides formed on exposed rock surfaces in arid regions.

    • ‘Many rocks in arid areas sport desert varnish, a dark, shiny coating rich in iron oxides and manganese oxide.’
    • ‘The stones in a pavement are usually coated with a desert varnish of materials deposited from water.’
    • ‘Scientists have developed a quick, easy, portable, and nondestructive way to determine the age of desert varnish, the mysterious dark coating that slowly develops on rocks in many arid regions of the world.’
    • ‘There are rocks formed in desert regions on the Earth, called desert varnish that form coatings by processes that are not well understood and at least some of these coatings look superficially like desert varnish.’
    • ‘The soil in this desert is unlike most I've come across in that there is a desert pavement, but it's very poorly developed and there's no desert varnish.’

Pronunciation:

desert varnish

/ˌdezərt ˈvärniSH/