Composition gold leaf is made up of copper and zinc which, when formulated correctly, closely resembles pure gold but is a fraction of the price. Our imitation silver leaf is made of an aluminum alloy. It gives the look of sterling silver, at a much lower cost, and will not tarnish like sterling silver. Copper leaf is 100% copper. It will tarnish, darken or patina if not sealed properly. However, much of the copper leaf techniques try to achieve the tarnish/patina effect. 5-1/2" x 5-1/2", 25 sheets per pack.