* Formation: Diamonds form deep within the Earth's mantle under intense heat and pressure. They are crystallized from carbon atoms bonded together in a specific crystal structure.

* Igneous Processes: Igneous rocks are formed from the cooling and solidification of molten rock (magma or lava). While diamonds don't directly form from magma or lava, the intense heat and pressure required for their formation are only found within the Earth's mantle, where igneous processes occur.

* Volcanic Activity: Diamonds are often brought to the surface through volcanic eruptions, embedded within kimberlite pipes. Kimberlite is an igneous rock that originates deep within the mantle and is responsible for transporting diamonds.

Key takeaway: While diamonds are not formed directly from magma, their formation and journey to the surface are deeply connected to the processes that create igneous rocks.