The individual geological history of the two mountains is relatively unknown. Marwa has been described as smoother and lighter in color than Safa, with some even calling it white, such as Majd ad-Din Ferozabadi, az-Zubaidi, al-Fayoumi. al-Alusi further went on to say that Safa's color was comparable to a tint of red. Safa and Marwa are a part of the Hejaz mountain range, which run parallel to most of the Saudi coast on the Red Sea. The Hejaz themselves are part of the larger Sarawat range, which is characterized by young and jagged mountains.