Its versatility, conductivity, durability and good looks make gold one of the five most expensive metals. However, there is another precious metal that beats this one in price.
The most expensive precious metal in the world is rhodium. As of today, an ounce of rhodium costs $4,200 (peaking at $28,775 per ounce in April 2021), while gold costs $1,923.25. And why is this metal, which many people don’t even know about, so expensive and valuable?
Rhodium is a rare precious metal that belongs to the platinum group metals (MGP) along with platinum, palladium, osmium, iridium and ruthenium due to its general hardness and high melting point of 1,964 degrees Celsius. Due to its scarcity, it is one of the most valuable metals in the world, often exceeding the price of gold.
Rhodium is often used in the automotive industry to produce catalysts that reduce harmful gas emissions. In recent years, despite a stable supply, demand for rhodium has increased significantly and is exceeding supply due to stricter emissions regulations and advances in the automotive industry.
This metal’s ability to withstand water and air temperatures of up to 600 degrees Celsius and its insolubility in most acids make rhodium very versatile for use in automobiles, aircraft, electrical contacts and thermocouples, and high resistance applications.
The metal, whose name comes from the Greek “rhodon,” meaning rose, is the rarest PGM. According to the Royal Society of Chemistry, it occurs in the earth’s crust at an amount of about 0.000037 parts per million, while gold accounts for about 0.0013 parts per million. There are more gold mines than rhodium.
Rhodium production occurs primarily in South Africa and Russia and can be a byproduct of copper and nickel refining. About 16 tons of rhodium are produced annually worldwide and reserves of the metal are believed to amount to 3,000 tons.
Rhodium was discovered in 1803 by the English chemist William Wollaston. Wollaston extracted rhodium from a piece of platinum in South America. Interestingly, the discovery came after the chemist discovered palladium, another platinum group metal.
Rhodium is usually found next to platinum deposits. Wollaston’s sample was obtained by removing platinum and palladium, leaving a dark red powder that was treated with hydrogen gas to reveal the precious metal.
While the solid metal shines in a bright, reflective silvery-white color, rhodium takes its name from the Greek “rhodon,” meaning rose. Its name refers to the red color of the metal salts.
Despite its rarity and beauty, 2019 statistics show that almost 90% of rhodium demand came from the automotive catalyst sector.
Rhodium prices vs. gold
Rhodium is a much rarer precious metal than gold and has recently traded at more than three times the price of gold. Due to the scarcity of rhodium, its distribution is approximately 1% of the availability of gold. There are many more gold mines than rhodium, which explains the huge price difference between the two.
Rhodium is used in more practical applications such as automotive, while gold is often decorative or alloyed with other metals. Gold is not as hard and durable as rhodium, which also contributes to its lower price.
The importance of PGMs in South Africa
South Africa is rich in various natural resources such as metals and minerals. In fact, almost all of the world’s MGP reserves are located in this country. In 2022, MGPs generated the largest share of revenue compared to other commodities in South Africa’s mining sector, worth R450 billion, the South African currency.
References:
- Johnson Matthey. https://matthey.com/products-and-markets/pgms-and-circularity/pgm-management/
- monetary metals. Rhodium Prices: View live and historical rhodium spot prices. https://www.moneymetals.com/rhodium-price
- Statista research department. July 2023. Monthly prices for rhodium worldwide 2019-2023. https://www.statista.com/statistics/1090402/price-for-an-ounce-of-rhodium-in-london-morning-fixing/
