Erythrite and Annabergite Rare mineral. On the surface of this rock, in the form of a green moss, one can see annabergite (Arsenate group). It is also called nickel bloom. Photo from 2 different viewpoints. Erythrite: Cobalt ore. Chemical formula: Co3[AsO4]2.8H2O. Crystal system: monoclinic. Annabergite or nickel bloom. Arsenate group. System: Monoclinic. Density: d3.1. Chemical formula: Ni3[AsO4]2.2H2O. Appears as aggregates of lamellar crystals of apple-green color. This is a rare product of the alteration of nickel-bearing sulfides. Add to basket
