Term: iridium (Ir)
Literally meaning: “pertaining to rainbow”
=éρις (gen ίριδος)/iris(=rainbow)>είρω/ero(=announce, say)
Iridium element named because of variety of colors which it gives while dissolving in marine acid.
Iridium was found in 1803 by English chemist Smithson Tennant (1761-1815). Iridium and osmium were identified in the black residue remaining after dissolving platinum ore with aqua regia ( a mixture of hydrochloric acid and nitric acid). Platinum was known in Europe from Spanish conquerors who found it in Colombia.
Iridium is a hard silvery-white chemical element with atomic number 77 and atomic mass 192,217. Iridium is the most corrosion--resistant metal known. It is used mainly as hardening agent for platinum alloys.