Description

• Blue verditer or blue bice is a name now given to an artificial basic copper carbonate, 2CuCO3.Cu(OH)2, which is
  similar in composition to the mineral, azurite.
  Blue verditer is a manufactured copper carbonate and was widely used as a wall paint in the 17th and 18th century, with
  a continuing use up to the 19th century.
  This synthetic azurite with a deep blue, slightly more greenish hue than the natural variety and lends itself to more even
  applications. Microscopically, blue verditer may be seen as tiny, rounded, fibrous aggregates, even in size and blue by
  transmitted light. It is similar in color to finely ground azurite.

  Historically, it was mixed with smalt for deeper shades. According to Laurie, the manufacture of blue verditer seems to
  have been carried on in England in large quantities at one time. Blue verditers were the best cheap substitutes for the
  more expensive azurite and ultramarine.
  Blue verditer is suited for tempera and watercolor, not for oil.