Blue verditer is basic copper (II)-carbonate: 2 CuCO3·Cu(OH)2 and it is the artificial form of the pigment azurite.It is stable in contact with the atmosphere and withstands higher temperatures up to its decomposition at approximately 300 °C and it is resistant to cold alkalis but is dissolved by dilute acids as all carbonates are. Its color can change to green because of its transformation to malachite. The pigment is considered lightfast.
Blue bice, Bremen blue, ashes bluePB 30, CI 77420The word ‘verditer’ comes from Old French verd de terre = earth green
The pigment can be prepared by the reaction of a solution of copper sulfate with calcium carbonate.
Blue verditer has been in use since the 17th-century not only by the artists but mainly by house painters.Examples of use