Selenium

What it is and where it is found
Selenium is mainly found as a trace element in the ore of copper, lead, zinc, gold and iron. When these metals are refined, selenium is precipitated. Selenium has a melting point of 221°C and a boiling point of 685°C. Its density is 4.819 g/cm³.

What it is used for
Selenium is used for many different purposes, from food supplements to animal feed and fertilizer additives and various applications in the electrical industry, in glass production, for chemicals and pigments. Selenium, however, is very toxic at higher concentrations. It is also needed in the production of manganese which, at least temporarily, has an effect on the not too abundant selenium supply.

How it is traded
Selenium is traded in the form of powders of various degrees of fineness.