Black botryoidal heterogenite specimen from Congo with green chrysocolla spots.
Close horizontal view of black botryoidal heterogenite and green chrysocolla.
Macro photograph of a glassy green chrysocolla nodule in heterogenite.
Cavernous blue green chrysocolla matrix with a black heterogenite rim.
Close view of teal chrysocolla interfacing with black botryoidal heterogenite.
Macro view of porous teal chrysocolla pockets with botryoidal textures.

Heterogenite & Chrysocolla

Heterogenite – Co3+O(OH)
Elements: Cobalt, Oxygen, Hydrogen
Class: Oxides
Crystal System: Hexagonal
Hardness: 3-5
Fluorite
Talc (1)Diamond (10)
Softer than glass. A steel knife scratches it.
Chrysocolla – (Cu,Al)2H2Si2O5(OH)4·nH2O
Elements: Copper, Aluminum, Hydrogen, Silicon, Oxygen
Class: Silicates
Crystal System: Orthorhombic
Hardness: 2-4
Calcite
Talc (1)Diamond (10)
A copper coin can scratch it.
Origin: ’Etoile du Congo Mine Lubumbashi, Haut-Katanga – Congo (drc)
Did you know?

Heterogenite looks like dull black tar on rock, easy to overlook. It is in fact the world's main ore of cobalt, the metal at the core of modern rechargeable batteries.

Chrysocolla is named from the Greek for gold and glue, because ancient jewelers used it to solder gold. Despite the name it holds no gold at all, and owes its blue-green color entirely to copper.

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