It is worth twice as much as gold and is much rarer. It is the most expensive metal in the world and this is what it is called.
Although platinum, gold and silver are the most commonly recognized precious metals, they are not the most expensive. This title belongs to rhodium, largely misunderstood and mainly used in automotive catalysts.
One gram of gold currently costs about $67 and the chance of finding it in the earth’s crust is 0.0013 parts in a million. For rhodium, however, the price is around $144 and the probability of finding it is 0.000037 parts per million, according to the Royal Society of Chemistry.
This metal was discovered in 1803 by the English chemist William Hyde Wollaston from a piece of platinum mined in South America. The metal was identified after palladium was discovered from the same sample, leaving behind a red powder, which turned out to be rhodium. Although silvery-white in solid state, its name in Greek means “rose”, referring to the red color of its salts.
Why is rhodium such an expensive metal?
Apart from its rarity, what makes rhodium so expensive is the fact that it does not readily react with oxygen i.e. it is resistant to corrosion and oxidation, making it an excellent catalyst.
Rhodium is part of the platinum group, melts (becomes liquid) at 1964 degrees Celsius, withstands water and air temperatures up to 600°C, and is not soluble in most acids. Thus, it has a wide variety of uses, ranging from catalysts to cars, airplanes, electrical contacts, high temperature thermocouples and resistance wires. Its use in jewelry is minimal and it is generally used in metal alloys.
Currently, about 16 tons of rhodium are mined each year, and it is estimated that only 3,000 tons remain in reserve. Its production takes place mainly in Russia and South Africa, and results from the refining of other ores, since no mine is dedicated to this metal.