Rhodium (Rh) is not radioactive and is the most expensive metal in the world. It is a rare member of the platinum group, with an annual worldwide demand of 32 tons. Palladium is the most expensive of the four major precious metals: gold, silver and platinum are the others. It is rarer than platinum and is used in large quantities for catalytic converters.
In the short term, demand for metals used in catalytic converters is expected to remain stable, driven by rising car sales in Asia. However, the increase in the adoption of battery-powered electric vehicles — which do not use catalytic converters — could affect demand for palladium. Rhodium is the most valuable metal and exists within the platinum group of metals. It is used in jewelry for a final finish on white gold jewelry.
It is found in the same mineral in which gold and silver exist, only in smaller quantities. This rare and valuable metal is often added as an alloy to its siblings, platinum and palladium, to increase toughness and strength. Rare metals, such as rhodium and gold, are so scarce that humans constantly reuse and recycle precious metals and diamonds. Gold is rare and desirable enough to be rare, possibly the metal most used in jewelry and industrial uses.
So what is the most valuable precious metal in jewelry? If gold or silver comes to mind, think again. The list of expensive precious metals and the figures mentioned below have been compiled from several sources on the web, such as 911Metallurgist & Gold Investments. In addition to their economic and industrial uses, gold and silver, platinum and other precious metals are popular for jewelry and art. Wollaston named the new metal rhodium, which has its roots in the Greek word for rose, rhodon, because of the reddish salts that dissolved in agua regia (aqua regia is a yellow-orange smoky liquid, named after alchemists because it can dissolve the noble metals gold and platinum).
It remains one of the most popular metals both in jewelry and as a repository of wealth in wallets, and is also desired for its durability and malleability. In its purest form, silver is found in the Earth's crust as an alloy with gold and other precious metals. Although it is also a catalytic metal, due to its high melting point and resistance to corrosion, iridium is the preferred material for crucibles. Most of the world's silver is produced as a by-product of refining gold, copper and other metals.
The annual production of rhodium is around 30 tons; to put that in context, gold miners extract between 2500 and 3000 tons of the precious metal annually. It can be found in the Earth's crust in its purest elemental form as an alloy with gold and other precious metals, and in minerals such as chlorargyrite and argentita. Rhenium is considered to be one of the rarest metals in the Earth's crust and has the third highest melting point and the second highest boiling point of all the stable elements.