Over millions of years, geological forces, such as volcanic activity and tectonic movements, can push the corundum crystals closer to the Earth’s surface. These crystals are often transported within molten rock called magma, which rises through cracks and fractures in the Earth’s crust. As the magma cools and solidifies, it forms igneous rocks. During this cooling process, the corundum crystals become trapped within igneous rocks, such as granite or basalt. This stage is crucial for the formation of rubies, as it provides the necessary conditions for the gem to develop its distinct characteristics.