Desert varnish

Petroglyphs carved in desert varnish at the Valley of Fire near Las Vegas, Nevada. Area shown is about 1 metre across.

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 micrometer thick and represents nanometre-scale layering. Rock rust and desert patina are other terms which are also used for the condition, but less often.

单词	Desert varnish
释义	Desert varnish 英语百科 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 micrometer thick and represents nanometre-scale layering. Rock rust and desert patina are other terms which are also used for the condition, but less often.
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