(named after the indigo line in the spectrum) Discovered by Reich and Richter in 1863. Found mainly with zinc minerals, iron, lead and copper. Somewhat rare, similar in abundance to silver. Canada produces the majority of supply.
used to make low-melting alloys, alloyed with gallium, germanium resistors, rectifiers, thermistors, photoconductors, plated onto metal or glass (for a mirror effect)