Who among you has visited a mountain or seen rocks of different colors and shapes? Why do you think the rocks are different? Let's find out together! 1. Igneous rocks: They are formed by volcanoes after magma (lava) cools. An example from the Saudi environment: the Harrat Rahat rocks south of Medina. Appearance: dark, hard, and perforated. 2. Sedimentary rocks: It is formed by the accumulation of layers of sand and clay over time. Local example: Rocks in the Great Nafud Desert. Its shape: clear layers, easy to crumble. 3. Metamorphic rocks: It is formed by the alteration of other rocks due to pressure and heat. Example: Metamorphic granite rocks in the Hejaz Mountains. Its shape: its colors are intertwined and strong.