This element, when overcome with extreme heat and pressure, creates diamonds.

Carbon is the element that, when subjected to intense heat and pressure, can transform into diamonds. This transformation occurs due to the rearrangement of carbon atoms, creating a tightly packed crystal lattice structure. Under extreme conditions found deep within the Earth's mantle, where temperatures reach thousands of degrees Celsius and pressure is extremely high, carbon atoms bond together and form the strong and precious gemstone known as a diamond.