Cook Island, Elizabeth II, Silver 20 Dollar Proof Coin, 2011, On both sides of the coin one can see and feel the convex shape of the big (25x36 mm) aquamarine blue "Swarovski stone", Obv: the stone glitters and reflects the light in its natural colours, Rev: the stone is covered with a silvery foil as a kind of mirror to give it an incredible glow, 100g, 55 x 85mm, UNC.