Erythrite or red cobalt is a secondary hydrated cobalt arsenate mineral with the formula Co ₃ ₂•8H ₂O. Erythrite and annabergite, chemical formula ₂•8H ₂O, or nickel arsenate form a complete series with the general formula ₃ ₂•8H ₂O. Erythrite crystallizes in the monoclinic system and forms prismatic crystals.
Colour: Crimson to peach red, ...
Hardness: 1½ - 2½
Member of: Vivianite Group
Name: Named in 1832 by Francois Sulpice Beaudant From the Greek έρυθρος for red.
From Ightem, Bou Azer District, Tazenakht, Ouarzazate Province, Souss-Massa-Draâ Region, Morocco.