Basic copper carbonate
Basic copper carbonate occurs naturally in two crystalline forms, blue (azurite) and green (malachite). Azurite and malachite have been used as gemstones and paint pigments since antiquity. They are prepared as pigments by careful selection, grinding, washing, and levigation. As coarsely ground particles, they give a deep opaque color, but when finely ground, the pigments give a lighter more transparent tone. Azurite and malachite are lightfast but are sensitive to acids and sulfur fumes. Basic copper carbonate can also be made artificially by coloring chalk with copper sulfate. The equivalent synthetic pigments, called blue verditer and green verditer, tend to have regularly sized particles with rounded edges.
Synonyms and Related Terms
basic cupric carbonate; azurite; malachite; carbonato básico de cobre (Esp.); carbonato basico di rame (It.); carbonato básico de cobre (Port.)
Insoluble in water and ethanol. Decomposes in acids with the evolution of carbon dioxide bubbles. Turns black with warm alkalis, hydrogen sulfide or sulfur fumes.
|Mohs Hardness||3.5 - 4.0|
|Melting Point||200 (dec)|
|Molecular Weight||mol. wt. = 221.13|
Hazards and Safety
Skin contact and inhalation may cause irritation or allergic reactions.
Chronic exposure may cause anemia.
Mallinckrodt Baker: MSDS
R. Gettens, and E. West Fitzhugh, "Azurite and Blue Verditer", Artists Pigments, Vol. 2., A. Roy ed. Oxford University Press, Oxford, 1993.
[[media:|Characteristics of Common Blue Pigments]]
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