Platinum is an extremely rare metal, occurring as only 0.003 ppb (Parts-per notation) in the earth’s crust, and is 30 times rarer than gold. It is sometimes mistaken for silver (Ag) but platinum is whiter in appearance. Platinum is often found chemically uncombined as native platinum and alloyed with iridum as platiniridium. Most often the native platinum is found in secondary deposits, and it is combined with the other platinum group metals in alluvial deposits. Platinum together with the rest of the platinum metals is obtained commercially as a by-product from nickel and copper mining and processing. During electro refining of copper, noble metals such as silver, gold and the platinum group metals as well as selenium and tellurium settle to the bottom of the cell as anode mud, which forms the starting point for the extraction of the platinum group metals.
Platinum occurs naturally in the alluvial sands of various rivers, though there is little evidence of its use by ancient peoples. However, the metal was used by pre-Columbian Americans near modern-day Esmeraldas, Ecuador to produce artifacts of a white gold-platinum alloy. 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 Darien and Mexico,
Platinum is an extremely much harder than gold. As a pure metal, platinum is silvery-white in appearance, lustrous, ductile, and malleable. It does not oxidize at any temperature, though it is corroded by halogens, cyanides, sulphur, and caustic alkalis. Platinum is insoluble in hydrochliric and nitric acid, though it does dissolve in aqua regia to form chloroplatinic acid, H2PtCl6.
Platinum’s wear- and tarnish-resistance characteristics are well suited for making fine jewellery. Platinum is more precious than gold and silver. Platinum, like other industrial commodities, is more volatile than gold.
During periods of sustained economic stability and growth, the price of platinum tends to be as much as twice the price of gold, whereas, during periods of economic uncertainty, the price of platinum tends to decrease due to reduced industrial demand, falling below the price of gold. Gold prices are more stable in slow economic times because gold is considered a safe haven and gold demand is not driven by industrial uses. In the 18th century, platinum’s rarity made King Louis XV of France declare it the only metal fit for a king. Platinum possesses high resistance to chemical attack, excellent high-temperature characteristics, and stable electrical properties. All these properties have been exploited for industrial applications. (Platinum bar Image)
The metal is extensively used in jewellery, wire, and vessels for laboratory use, and in many valuable instruments. It is also used for electrical contacts, corrosion-resistant apparatus, and in dentistry.