Platinum
Platinum is a member of the platinum group of elements and group 10 of the periodic table of elements. It has six naturally occurring isotopes. It is one of the rarer elements in Earth's crust, with an average abundance of approximately 5 μg/kg. It occurs in some nickel and copper ores along with some native deposits, mostly in South Africa, which accounts for 80% of the world production. Because of its scarcity in Earth's crust, only a few hundred tonnes are produced annually, and given its important uses, it is highly valuable and is a major precious metal commodity.
Pierre-François Chabaneau
Chabaneau was able to easily remove most of platinum's natural impurities, including gold, mercury, lead, copper, and iron, leading him to believe that he was working with pure platinum. However, the metal displayed inconsistent characteristics. At times it was malleable, yet at times it was highly brittle. Sometimes it was entirely incombustible, yet sometimes it burned readily. These inconsistencies were a result of various impurities: rhodium, palladium, osmium, iridium, and ruthenium. These elements would later come to be known as the platinum group metals, but at the time of Chabaneau's research, they had not yet been discovered.