Chalconatronite

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Formula: Na₂Cu(CO₃)₂.3H₂O
Valence: Na₂Cu²⁺(CO₃)₂.3H₂O
Hydrated carbonate, copper-bearing mineral
Crystal system: Monoclinic
Specific gravity: 2.27 measured, 2.31 calculated for synthetic material
Colour: Greenish blue to pale blue
Solubility: Partly decomposed by water, completely soluble in cold acid with effervescence
Environments

Hydrothermal environments

Chalconatronite can crystallise on the surface of archaeological copper objects (artefacts) which have been treated with an aqueous Na₂CO₃ solution in order to stabilise them (Mindat).

Localities

At the Carr Boyd Rocks Ni mine, Menangina Station, Menzies Shire, Western Australia, chalconatronite is an uncommon secondary mineral in the oxidation zone of polymetallic deposits. Associated minerals include paratacamite, gypsum, brochantite, malachite, azurite, epsomite, nickel-bearing magnesite, glaukosphaerite, takovite, georgeite and carrboydite (HOM).
Chalconatronite from the Carr Boyd Rocks Ni mine - Image

The type locality is Egypt. Chalconatronite was originally found as a fine-grained, greenish blue crust, as an alteration of bronze (an alloy primarily of copper with subsidiary tin) artifacts. Associated minerals include atacamite and cuprite (Mindat).
Chalconatronite from a shipwreck - Image

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