Named in 1845 in honor of the English mineralogist ( ) William Miller (1801-1880) ( ) who first studied the crystals, this mineral forms as a low-temperature mineral often in cavities and as an alteration of other nickel minerals. It is commonly found as radiating and jack-straw clusters of shiny metallic acicular crystals, pale brass-yellow with an iridescent tarnish.

Mineral Photos courtesy of R.Weller/Cochise College