Gold is a chemical element with the symbol Au (from Latin: aurum) and atomic number 79, making it one of the higher atomic number elements that occur naturally.

Nickel belongs to the transition metals and is hard and ductile and is used in many specific industrial and consumer products such as stainless steel, special alloys, alnico magnets and rechargeable batteries.

Copper is a ductile metal with very high thermal and electrical conductivity and is used as a conductor of heat and electricity, a building material, and a constituent of various metal alloys.

Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a blue-silvery appearance when oxidation is removed. It is the first element in group 12 of the periodic table.

Cobalt is a chemical element with the symbol Co and atomic number 27. Like nickel, cobalt is found in the Earth’s crust only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.