And in some countries, the strength of the national currency is measured by the amount of accumulated gold in their central banking system. The jewelry application is still important and gold jewelry is prized by everyone worldwide. The dental applications have declined over the years with the development of alloys of base metals that are either equivalent to or in some cases better than gold. And in these days of tight budgets, the fact that the alternatives are significantly lower in price make them even more attractive. And of course there are applications ranging from electronics to medicine for this most interesting of metals.
Iridium is the most inert of the precious metals.
Its chemical resistance is legend, and is superior in that respect to gold and platinum, while featuring a far higher melting point. As a result, it is used for making crucibles and other apparatus for use at high temperatures. It is also used in certain electrical contacts and also, a hardening agent for platinum. We have been told that in the past, osmium metal was used for phonograph needles because of its outstanding resistance to chipping and wear. Today, the uses for osmium are somewhat different.