Copper(II) carbonate is a blue-green solid. It is made when copper is in air for a long time and turns green. The other part of that coating is copper(II) hydroxide. It dissolves in acids to make carbon dioxide and a copper salt. It breaks down when heated to make carbon dioxide and copper(II) oxide.
It can irritate the skin. It is toxic since it dissolves in stomach acid to make copper ions in solution, which can be absorbed.