Blue krohnkite with green natrochalcite from Chile showing mirror reflection.
Close front view of blue krohnkite and green natrochalcite crystals.
Angled profile view of fibrous blue krohnkite with green natrochalcite.
Detailed view of layered blue krohnkite and green natrochalcite matrix.
Transillumination view of glowing neon blue krohnkite and green natrochalcite.
Krohnkite & Natrochalcite video

Krohnkite & Natrochalcite

Kröhnkite – Na2Cu(SO4)2·2H2O
Elements: Sodium, Copper, Sulfur, Oxygen, Hydrogen
Class: Sulfates
Crystal System: Monoclinic
Hardness: 2.5-3
Calcite
Talc (1)Diamond (10)
A copper coin can scratch it.
Natrochalcite – NaCu2(SO4)2(OH)·H2O
Elements: Sodium, Copper, Sulfur, Oxygen, Hydrogen
Class: Sulfates
Crystal System: Monoclinic
Hardness: 4.5
Apatite
Talc (1)Diamond (10)
Softer than glass. A steel knife scratches it.
Size: 5.7 x 4.6 x 4.3 cm Origin: Chuquicamata Mine, Calama, Antogasta – Chile
Did you know?

Krohnkite is a sky-blue copper mineral from the Atacama Desert that survives only where it never rains. So soluble it would wash away in a single shower, it exists thanks to the driest air on Earth.

Natrochalcite shows emerald-green crystals that look tropical, but it is a desert mineral through and through. Bound with the sodium of common salt, this copper sulfate forms only in the rainless Atacama.

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