Some of the well-known ETFs include iShares Silver Trust (with ticker symbol NYSE: SLV), Central Fund of Canada (with ticker symbols TSX: CEF.NV.A, NYSE: CEF), and ETFS Silver Trust (with ticker symbol NYSE: SIVR). Trading in ETFs means doing away with the inconveniences associated with the handling of physical silver bars. Iridium is named after the Latin word "iris", which means "rainbow". 5. Rhodium - William Hyde Wollaston discovered rhodium in 1803, shortly after he discovered palladium. He discovered this precious metal from crude platinum samples obtained from South America. The name rhodium was derived from the Greek word "rhodon", which means "rose". With an average mass fraction of 0.05 parts-per notation in the continental crust, osmium is known to be one of the least abundant elements in the Earth's crust. It is found in nature in natural alloys or as a pure element. Similar to the other precious metals in the platinum group, osmium can be found in alloys with copper or nickel. Rhenium resources are identified in several countries, which include Chile, Peru, Armenia, Mexico, Russia, Canada, Kazakhstan, and Uzbekistan. The estimated total resource from these eight countries is 6,000 tonnes (6 million kilograms). The United States alone, on the other hand, has an estimated total resource of 5,000 tonnes (5 million kilograms). As to its other applications, ruthenium is used in: 1. film chip resistors; 2. jewelry (when alloyed with gold); 3. high-temperature superalloys (used in making the turbine blades in jet engines); 4. fountain pen nibs; 5. removing hydrogen sulfide from various industrial processes; 6. electrolytic cells for various chemical processes (as a component of mixed-metal oxide anodes); 7. Silver: Silver compounds (example, colloidal silver), when absorbed into the body, may cause argyria, a condition characterized by the bluish-gray pigmentation of the skin, mucous tissues, and the eyes. While the condition is not really harmful to one's health, it is often permanent. Otherwise, silver per se is not at all toxic.