This concentration of iron oxide causes a red colouration and is one notable aspect of Wadi Rum. Across southern Jordan, places get their names from the ochre hues in the sand, including the Nabatean city of Petra.

The iconic crimson hue of the sand in Jordan's Wadi Rum is the result of iron oxide (hematite) coating the individual grains of quartz. Geologically, the area is dominated by the Umm Ishrin Sandstone formation, which is rich in iron minerals. Over millions of years, the natural weathering and erosion of these ancient sandstone mountains have released iron-rich particles that oxidize—essentially "rusting"—when exposed to the atmosphere. This thin veneer of iron oxide "frosts" the translucent quartz sand, creating the vibrant shades of red, orange, and maroon that give the "Valley of the Moon" its Martian appearance. Interestingly, the intensity of the red color can shift depending on the time of day and the moisture content; after a rare rain, the sand can appear much darker and more dramatic. This natural pigment is so pervasive that it has been used by local Bedouin tribes for centuries as a natural dye and is the primary reason why Wadi Rum is a world-renowned filming location for movies set on other planets.