A desert pavement, also called reg (in the western Sahara), serir (eastern Sahara), gibber (in Australia), or saï (central Asia),  is a desert surface covered with closely packed, interlocking angular or rounded rock fragments of pebble and cobble size. They typically top alluvial fans.

Desert varnish collects on the exposed surface rocks over time. It is an orange-yellow to black coating. Desert varnish is usually around one micrometer thick. Rock rust and desert patina are other terms which are also used for the condition, but less often.

Desert varnish forms only on physically stable rock surfaces that are no longer subject to frequent precipitation, fracturing or wind abrasion. The varnish is primarily composed of particles of clay along with iron and manganese oxides. There is also a host of trace elements and almost always some organic matter.

The desert known as Reg in Western Sahara with larger rocks is shown in the figure.