The Most Expensive Precious Metal in the World, Not Gold

Dream - Thanks to its versatility, conductivity, durability, and luxurious appearance, gold is among the top five most expensive metals.

The price of gold reached US$1,897 per troy ounce (equivalent to Rp933,147 per gram) at the time of publication. This price always experiences an increase although it takes quite a long time.

From ancient times until now, gold in the form of jewelry has always been highly regarded.

A country can even be destroyed due to the fight over gold. The value of currency can be devastated just because of gold.

But gold is nothing compared to a metal called rhodium.

Not only is it the most expensive, rhodium is also the rarest precious metal in the world today.

The price per troy ounce of rhodium reaches US$4,200 (equivalent to Rp2,065,500 per gram) at the time of publication.

So, what makes rhodium so expensive that gold has to 'kneel beneath it'?

Unlike gold, rhodium does not easily react to oxygen.

This makes rhodium a precious metal and a perfect catalyst. Rhodium is resistant to corrosion and oxidation.

Its overall durability and high melting point of 1,964 degrees Celsius place it in the platinum group of metals.

In addition to rhodium, other platinum group metals are platinum, palladium, osmium, iridium, and ruthenium.

Rhodium also has the ability to withstand water and air temperatures up to 600 degrees Celsius.

Another greatness of rhodium is that it is insoluble in most acids, making it very versatile in various industries.

Rhodium can be used in cars, airplanes, electrical contacts, high-temperature thermocouples, and resistance cables.

As the rarest metal in the platinum group, the content of rhodium in the Earth's crust is only about 0.000037 parts per million.

Meanwhile, gold is found in abundant amounts, around 0.0013 parts per million, according to the Royal Society of Chemistry.

Produced mainly in South Africa and Russia, rhodium is a by-product of copper and nickel ore refining. From this refining process, only 0.1 percent contains rhodium.

Nevertheless, around 16 tons of rhodium are produced each year, with estimated reserves of 3,000 tons.

The discovery of rhodium occurred in 1803 by William Hyde Wollaston, an English chemist.

At that time, he accidentally discovered it while extracting the element from a piece of platinum ore from South America.

The discovery of rhodium happened not long after Wollaston discovered other platinum group metals, palladium.

Usually found together with platinum deposits, rhodium is obtained by removing platinum and palladium.

This process leaves a dark red powder that is processed with hydrogen gas to reveal the precious metal rhodium.

While its solid form emits a bright silver-white color and luster, rhodium gets its name from the Greek word "rhodon" which means rose. Its name refers to the red color of the salts found in the metal.

Despite its rarity and beauty, statistics from 2019 show that almost 90 percent of the demand for rhodium comes from the automotive catalyst sector in catalytic converter production.

These statistics reveal the unusual usage of one of the rarest precious metals on Earth.

Source: IFL Science