Class : Oxides and hydroxides
    Subclass : Hydroxides and hydrates
    Crystal system : Hexagonal
    Chemistry : CoO(OH)
    Rarity : Uncommon

Heterogenite is a fairly rare oxide, present in the oxidation zone of cobalt deposits, where it comes from the alteration of sulfides and arsenides of this metal (linneite, smaltine, skutterudite). It is also a residual mineral widespread in soils derived from the alteration of ultrabasic rocks (New Caledonia). Heterogenite has two dimorphs : 3R heterogenite and the much rarer 2H heterogenite. Nickel contents are common and reach up to 2%. Its name is taken from the Greek heteros (other) and genês (kind) which thus highlights the fact that its chemical composition is different from similar minerals. Heterogenite is a black mineral, rarely dark red-brown (steel gray for the 2H dimorph), constituting coatings, botryoidal or stalactitic masses, with an earthy or powdery appearance. Hexagonal prismatic crystals are exceedingly rare and do not exceed a millimeter in size. Heterogenite was once exploited as cobalt ore.

Main photo : Heterogenite on chrysocolla from L'Etoile du Congo Mine, Katanga, D.R. Congo © Benjamin Oelker

No twin known for this mineral species.

No fakes recorded for this mineral species.