Multiple choice Which of the following forms part of the verdigris patina? Columbite Copper(II) carbonate Copper(II) chloride Copper(II) hydroxide Reveal answer Fill a bubble to check yourself B Correct answer Explanation Copper(II) carbonate is a blue-green compound (chemical formula CuCO3) forming part of the verdigris patina that is found on weathered brass, bronze and copper.