Annabergite
Annabergite
A monoclinic mineral, 2[Ni3(AsO4)2.8H2O]; vivianite group with cobalt replacing nickel toward erythrite; occurs as light-green soft coatings of fine striated crystals, or earthy; an oxidation product of nickel and cobalt arsenides, the green crusts being a distinctive guide to nickel ores. Formerly called nickel ocher.