iridium

 
Pronunciation: /ɪˈrɪdɪəm, ʌɪ-/

noun

[mass noun]
  • the chemical element of atomic number 77, a hard, dense silvery-white metal. (Symbol: Ir)

Origin:

early 19th century: modern Latin, from Latin iris, irid- 'rainbow' (so named because it forms compounds of various colours)