Desert varnish is a coating on aerially exposed desert rocks that is primarily composed of ____________.

Question

Quizplus · Accepted Answer

Desert varnish is primarily composed of iron and manganese-oxides, which are typically derived from wind-blown dust and soil particles that contain these elements. Over time, these minerals accumulate on the surface of rocks and form a thin, dark coating that is characteristic of desert environments. While other minerals such as quartz and calcite may also be present in desert varnish, they are not the primary components. Choice A and B are incorrect because microcrystalline quartz and calcite are not typically found in desert varnish. Choice C is partially correct, as aluminum oxides and hydroxides may also be present in some desert varnish samples, but they are not the primary component.

Desert Varnish Is a Coating on Aerially Exposed Desert Rocks