When the world’s most precious and rare metals are considered, the first thing that comes to mind will be gold. But this relatively high-ranking metal is actually not in the first place in terms of both price and rarity.
Monetary values of different metals are inconsistent as they vary slightly depending on demand and availability. Gold is almost certainly among the top five most expensive metals due to its wide use, conductivity, durability and beautiful appearance. While gold prices (around $1,850 per ounce as of this writing) are pretty impressive, they’re really insignificant compared to rhodium.
Rhodium, currently one of the most expensive and rarest metals, costs around $10,300 per ounce at the time of this writing. There are several different reasons why rhodium is so valuable.
What is rhodium; Why is it valuable?
Rhodium does not react readily with oxygen, which makes it a noble metal and means it is an excellent catalyst resistant to both corrosion and oxidation. Its overall toughness and high melting point of 1,964 degrees Celsius places it among the platinum group metals alongside platinum, palladium, osmium, iridium and ruthenium.
Withstanding water and air temperatures up to 600 degrees Celsius and remaining insoluble in most acids, rhodium makes it versatile for use in cars, airplanes, electrical contacts, and high-temperature thermocouple and resistance wires.
As the Royal Society of Chemistry states, rhodium, the rarest of the platinum group metals, has about 0.000037 parts per million in the Earth’s crust, while gold has about 0.0013 parts per million. Mainly produced in South Africa and Russia, rhodium can be found as a byproduct of refining copper and nickel ores containing up to 0.1 percent precious metals. About 16 tons of rhodium are produced annually and reserves are estimated to be around 3,000 tons.
Rhodium was discovered in 1803 by English chemist William Hyde Wollaston, who extracted the element from a piece of platinum ore from South America. Wollaston made this finding shortly after he discovered palladium, another platinum group metal.
Rhodium, often found with platinum deposits, was obtained by extracting platinum and palladium from Wollaston’s sample and treating the remaining dark red powder with hydrogen gas to reveal the precious metal Rhodium.
The solid metal that shines with a bright, reflective silver-white color, rhodium derives its name from the Greek word “rhodon” meaning rose. This name refers to the red color of metal salts.
Despite its rarity and beauty, 2019 statistics show that almost 90 percent of demand for rhodium comes from the autocatalyst industry in the manufacture of catalytic converters, which probably doesn’t seem like a good use for one of the Earth’s rarest precious metals.
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