 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 . 
