Polymer clay can copy so many things in this world and shimmering look of diachronic glass is among one of them. With the little efforts you can also create fake or similar diachronic glass by using Mylar backed foils. Many brands made this type of foil but important is to have a right technique to give the right look. Rolled out the flat sheet of polymer clay and then apply the design side facing the clay is the best way to achieve the success and then hard should be used to burnish it to the clay. In order to release the foil from Mylar backing you must create the friction that creates heat and run the card on the foil many times as it takes few minutes but help you to get the design the foil.
Just pull the Mylar film away from the foil in a second just like a band aid when you think you have created enough friction. At this point when Mylar film completely removes from the foil it should be stuck to the polymer clay. You can cut these foil strips after removing the Mylar film into different decorative pieces such as jewelry, pendants, house wares etc.