The Metals

Copper (Cu, atomic number 29) is a reddish transition metal with outstanding electrical and thermal conductivity, regarded as the oldest metal deliberately used by humans and today an indispensable industrial raw material.

Gold (chemical symbol Au, atomic number 79) is a yellow, corrosion-resistant precious metal that has been used for thousands of years as a store of value, a currency metal and a material.

Iridium (Ir) is a silver-white platinum group precious metal with one of the highest densities of all elements (22.56 g/cm3, just behind osmium) and exceptional corrosion resistance.

Osmium (Os, atomic number 76) is the densest naturally occurring element on Earth and belongs to the platinum group of metals.

Palladium (Pd, atomic number 46) is a silvery-white platinum group precious metal used above all as a catalyst in vehicle exhaust systems and in the electronics industry.

Platinum is a rare, silvery-white precious metal of the platinum group metals with atomic number 78, regarded as one of the most valuable metals on Earth because of its exceptional corrosion resistance, catalytic properties and industrial versatility.

Platinum group metals (PGM) are six chemically related transition metals – platinum, palladium, rhodium, iridium, osmium and ruthenium – distinguished by exceptional corrosion resistance, high melting points and catalytic properties.

Precious metals form a group of chemical elements marked by strong resistance to corrosion and oxidation, which in nature turn up mostly in native form – that is, as pure metal.

Rhodium (Rh) is a silvery-white platinum-group precious metal used above all as a catalyst in vehicle exhaust systems and for surface finishing, and it ranks among the rarest and most expensive metals on Earth.

Ruthenium (Ru) is a scarce platinum group metal prized for outstanding hardness and corrosion resistance, deployed mainly in electronics and as an alloying additive.

Semi-precious metals are metals that show a certain resistance to corrosion but do not possess the full chemical resistance of the precious metals.

Silver (Ag) is a white-lustrous precious metal with the highest electrical conductivity of all elements and is used both as an investment metal and in industry, photography and medicine.

White gold metals are those precious and base metals that give gold a silvery-white colour when used as alloying partners — above all palladium, platinum and nickel.