A precious metal is a rare, naturally occurring metallic chemical element and has high economic value. Such precious metals are chemically less reactive than most elements. They are usually ductile and have a high lustre. * ppb = parts per billion – The abundance of the element, a measure for its rarity, is given in mass fraction as kg in the earth’s crust.
Rhenium
Atomic Number: 75
Symbol: Re
Rarity: 0.7ppb
History: Discovered in 1925, rhenium was the last stable element to be discovered. It was named after the river Rhine in Europe.
Applications/Uses: Rhenium is added to high-temperature superalloys that are used to make jet engine parts, using 70% of the worldwide rhenium production. Another major application is in platinum-rhenium catalysts, which are primarily used in making lead-free, high-octane gasoline.
Iridium
Atomic Number: 77
Symbol: Ir
Rarity: 1ppb
History: Iridium was discovered in 1803 among insoluble impurities in natural platinum. Smithson Tennant, the primary discoverer, named the iridium for the goddess Iris.
Rhodium
Atomic Number: 45
Symbol: Rh
Rarity: 0.7ppb
History: Rhodium was discovered in 1803 by William Hyde Wollaston in an ore of platinum or nickel, and was named for the rose color of one of its chlorine compounds, produced after it reacted with the powerful acid mixture aqua regia.
Applications/Uses: catalytic converter; glass industry, mostly for production of fiberglass and flat-panel glass; Rhodium detectors are used in nuclear reactors to measure the neutron flux level.
Ruthenium
Atomic Number: 44
Symbol: Ru
Rarity: 1ppb
History: Russian scientist, Karl Ernst Claus, discovered the element in 1844 and named it after Ruthenia, the Latin word for Rus’ (ancient Russia).
Applications/Uses: Used for wear-resistant electrical contacts and the production of thick-film resistors; platinum alloys.
Tellurium
Atomic Number: 52
Symbol: Te
Rarity: 1ppb
History: Tellurium was discovered in Transylvania (today part of Romania) in 1782 by Franz-Joseph Müller von Reichenstein in a mineral containing tellurium and gold. Martin Heinrich Klaproth named the new element in 1798 after the Latin word for “earth”, tellus.
Applications/Uses: It is used in iron, copper and lead alloys; it makes stainless steel and copper more machinable; it improves strength and durability of lead; it decreases the corrosive action of sulfuric acid.
Osmium
Atomic Number:76
Symbol: Os
Rarity: 1.5ppb
History: Osmium (from Greek “osme” meaning “smell”) was discovered in 1803 by Smithson Tennant and William Hyde Wollaston in London, England.
Applications/Uses: Its alloys with platinum, iridium, and other platinum group metals are employed in fountain pen tips, electrical contacts, and other applications where extreme durability and hardness are needed.
Gold
Atomic Number:79
Symbol: Au
Rarity: 4ppb
History: Gold has been a valuable and highly sought-after precious metal for coinage, jewelry, and other arts since long before the beginning of recorded history.
Applications/Uses: Monetary exchange; Investment; Jewelry; Medicine; Food and drink; Industry; Electronics; Commercial chemistry.
Platinum
Atomic Number:78
Symbol: Pt
Rarity: 5ppb
History: Its name is derived from the Spanish term platina, which is literally translated into ‘little silver’. The first European reference to platinum appears in 1557 in the writings of the Italian humanist Julius Caesar Scaliger as a description of an unknown noble metal found between Darién and Mexico, “which no fire nor any Spanish artifice has yet been able to liquefy”.
Applications/Uses: Platinum is used in catalytic converters, laboratory equipment, electrical contacts and electrodes, platinum resistance thermometers, dentistry equipment, and jewelry.
Bismuth
Atomic Number:83
Symbol: PBit
Rarity: 8.5ppb
History: Bismuth metal has been known from ancient times, but its name possibly comes from Arabic ‘bi ismid’, meaning having the properties of antimony or German words ‘weisse masse or wismuth’ (white mass), translated in the mid sixteenth century to New Latin ‘bisemutum’.
Applications/Uses: Pharmaceuticals, pigments, cosmetics, metallurgical additives for casting and galvanizing, bismuth alloys, solders and ammunition.
Palladium
Atomic Number: 46
Symbol: Pd
Rarity: 15ppb
History: It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired by her when she slew Pallas.
Applications/Uses: Catalytic converters, electronics, dentistry, medicine, hydrogen purification, chemical applications, and groundwater treatment.
Silver
Atomic Number: 47
Symbol: Ag
Rarity: 75ppb
History: Silver has been known since ancient times. The chemical symbol “Ag” is from the Latin for silver, argentum, from the Indo-European root *arg- meaning ‘white’ or ‘shining’.
Applications/Uses: Investment, to make ornaments, jewelry, high-value tableware, utensils, currency coins, electrical contacts and conductors, in mirrors and in catalysis of chemical reactions.
Mercury
Atomic Number:80
Symbol: Hg
Rarity: 85ppb
History: Mercury was found in Egyptian tombs that date from 1500 BC.
Applications/Uses: Mercury is used primarily for the manufacture of industrial chemicals or for electrical and electronic applications. It is used in some thermometers, especially ones which are used to measure high temperatures. A still increasing amount is used as gaseous mercury in fluorescent lamps.
Indium
Atomic Number:49
Symbol: In
Rarity: 250ppb
History: German chemists Ferdinand Reich and Hieronymous Theodor Richter discovered it in 1863 while doing spectroscopy and named the element with the blue spectral line indium, from the indigo color seen in its spectrum.
Applications/Uses: coating for bearings in high-performance aircraft engines, fusible alloys, solders, and electronics, semiconductors, liquid crystal displays (LCD).
Germanium
Atomic Number:32
Symbol: Ge
Rarity:1500ppb
History: In 1886, Clemens Winkler found the new element along with silver and sulfur, in a rare mineral called argyrodite and named the element after his country, Germany.
Applications/Uses: Germanium “metal” (isolated germanium) is used as semiconductor in transistors and various other electronic devices. PET bottles.
Beryllium
Atomic Number:4
Symbol: Be
Rarity: 2800ppb
History: The original source is probably the Sanskrit word vaidurya, which is of Dravidian origin and could be derived from the name of the modern city of Belur.
Applications/Uses: Beryllium increases hardness and resistance to corrosion when alloyed to aluminium, cobalt, copper (notably beryllium copper), iron and nickel. In structural applications, high flexural rigidity, thermal stability, thermal conductivity and low density (1.85 times that of water) make beryllium a quality aerospace material for high-speed aircraft, missiles, space vehicles and communication satellites.
Gallium
Atomic Number:31
Symbol: Ga
Rarity: 19000ppb
History: In 1871, existence of gallium was first predicted by Russian chemist Dmitri Mendeleev, who named it “eka-aluminium” on the basis of its position in his periodic table. Gallium was discovered spectroscopically by Paul Emile Lecoq de Boisbaudran in 1875 by its characteristic spectrum (two violet lines) in an examination of a sphalerite sample.
Applications/Uses: Gallium is used for microelectronics, microwave circuitry and infrared applications, minority semiconductor uses, produce blue and violet light-emitting diodes (LEDs) and diode lasers.