Iridium, a metal of the platinum family, is white (similar to platinum) but with a slight yellowish cast. Because iridium is very hard and brittle, it is hard to machine, form, or work.Iridium is not attacked by any of the acids nor by aqua regia, but is attacked by molten salts, such as NaCl and NaCN.
Melting point: 2446 °C Boiling point: 4428 °C
A foil is a thin sheet of pure metal. Given its fragile nature, some foils have protective coatings.