There are a few conjectures as to what the D  stands for. Some have said💶 it is an abbreviation for departure  or decision.  Others claim that it stands for doomsday.💶  However, according to the United States military, the origin of the popular nickname has more to do with their💶 terminology.

Other Name(s): Atomic number 28, Chlorure de Nickel, Ni, Nickel Chloride, Nickel Sulfate, Nickelous Sulfate, Nquel, Numro💪 Atomique 28, Oligo-lment, Sulfate de Nickel, Sulfate Nickeleux, Trace Element.

Nickel minerals were green, like copper ores, and💪 were known as kupfernickel  Nickel's copper  because they produced no copper.