Nickel, represented by the symbol Ni and atomic number 28, is a remarkable chemical element. Displaying a silvery-white lustrous appearance with a delicate golden hue, nickel qualifies as a hard and ductile transition metal. Although pure nickel exhibits chemical reactivity, it forms a protective layer of nickel oxide on its surface when exposed to air, impeding further corrosion. Despite its scarcity in Earth’s crust, pure native nickel can be found in minute quantities, primarily in ultramafic rocks, as well as within the interiors of larger nickel–iron meteorites that remained shielded from oxygen while outside Earth’s atmosphere.