Desert varnish

Ok, kiddo. Desert varnish is a special kind of coating that forms on rocks that are found in the desert. It is made up of a mixture of clay, minerals, and tiny bits of things like dead bugs and bits of plants.

So, when it rains in the desert (which is not very often), the water can soak into the rock and mix with all the little bits that are on the surface. Then, as the water starts to evaporate and dry up, it leaves behind this special coating that can range in color from black or brown to reddish orange.

One really amazing thing about desert varnish is that it can actually protect the rocks that it's on from weathering and erosion. So even though it may look kind of dirty, it's actually helping to keep the rocks strong and durable.

Scientists aren't exactly sure how desert varnish forms, but they think it has something to do with bacteria and other tiny organisms that live on the surface of the rocks. So, even though it may not look like much, desert varnish is actually a pretty fascinating natural phenomenon!