Only a quarter of the Sahara Desert is sandy.

Only a quarter of the Sahara Desert is sandy.

Sand dunes and sheets cover only around 25% of the Sahara's actual surface. This desert also has numerous other land features including salt flats, gravel plains, plateaus and even mountains where snow has been recorded.

The Sahara is much more than just sand – in fact, the majority of the Sahara is made up of barren, rocky plateaus, as well as salt flats, sand dunes, mountains and dry valleys. The rivers and streams found in the Sahara are all seasonal, apart from the River Nile.

Where did the massive amount of the sand that forms the Sahara Desert come from? The sand is primarily derived from weathering of Cretaceous sandstones in North Africa. ... These mountains are volcanic and intrusive, and the granite rock weathers out to leave behind quartz sand grains that are carried by rivers to the sea.

Although many deserts are sand-covered, most are not. Many desert landscapes are rocky surfaces. They are rocky because any sand-size or smaller particles on the surface are quickly blown away. Rocky deserts are barren wind-swept landscapes.

The principal topographical features of the Sahara include shallow, seasonally inundated basins (chotts and dayas) and large oasis depressions; extensive gravel-covered plains (serirs or regs); rock-strewn plateaus (hammadas); abrupt mountains; and sand sheets, dunes, and sand seas (ergs)