If gold is relatively rare and most of it has already been mined, does it have much of a future? One thing to remember is that a significant portion of the world's supply of gold is held in reserve by central banks or by individuals who keep gold as an investment. By some estimates, so-called "bar hoarding" accounts for nearly 236 tons (214 metric tons) of gold [source: National Geographic]. Recycling also plays an important role. Approximately 85 percent of all the gold ever found is still being used today, which means that the gold in your favorite jewelry could have once glittered from the headdress of an Incan or Aztec king [source: Temescu].
Some scientists are looking to the heavens to find more gold. In 1998, the Near Earth Asteroid Rendezvous (NEAR) spacecraft passed close to the asteroid Eros and sent back data indicating that the potato-shaped space rock was a vast warehouse of metals. If Eros is typical of stony meteorites that crash to Earth, then it contains about 3 percent metal. Given the dimensions of the asteroid, NASA scientists estimate that Eros may house 20 billion tons (18.1 billion metric tons) of gold and similar amounts of other metals, such as aluminum and platinum [source: BBC News].
Back on Earth, prospectors continue to search for new gold deposits using new, highly sensitive methods of detection. These new methods greatly increase the odds that once-overlooked gold will be discovered. For example, a gold mine near Carlin, Nev., is producing gold from a large low-grade deposit that was opened in 1965 after intensive scientific and technical work had been completed. Other such deposits most certainly exist.
Wherever new mines are established, mining companies will need to focus more on the environmental impact of their operations. Extracting a single ounce of gold requires the removal of 250 tons (227 metric tons) of rock and ore [source: National Geographic]. Then there's the effluent -- the cyanide-laced liquid from the extraction and refining processes -- that's most often dumped offshore. "No Dirty Gold," a campaign run by the nonprofit Earthworks, seeks to raise the environmental standards of the global mining industry. The campaign has enlisted the support of 30 of the world's leading jewelry companies, persuading them to stop selling gold from mines with questionable practices.
Such a campaign is unlikely to stop the global demand for gold. But perhaps it will make us realize that the gold rings on our fingers have a life and a history far beyond our own.