Copper  goes back to prehistoric times; it has been mined for more than 6000 years.

Selenium is a trace mineral that is essential to good health.  Selenium is incorporated into proteins to make selenoproteins, which are important antioxidant enzymes. The antioxidant properties of selenoproteins help prevent cellular damage from free radicals. Free radicals are natural by-products of oxygen metabolism that may contribute to the development of chronic diseases such as cancer and heart disease. 

Iron is probably the most precious of all metals, since man would certainly miss this element more than any other, even the so-called precious ones.

Cobalt is not an abundant element but is widely diffused in rocks, sea and mineral waters, coal, meteorites, the sun and stellar atmospheres, soils, plants and animals.

Indium is considered a non-toxic element, with no serious accident having been reported with this element.

Silver constitutes about 0.07 parts per million in the earth’s crust. In seawater, the concentration may be as high as 0.000,002 parts per million. Food stuffs including dairy products tend to accumulate metals such as silver. In a normal diet, a person may ingest 30 to 40 parts per million (30 to 40 micrograms) per day. Mushrooms, for example, may boost silver consumption up to between 200 to 300 micrograms per day.