Foilback

A method of coating the back of a stone with silver, gold, or colored foil. This enhances the brilliancy of the stone, by reflecting back as much light as possible. It is commonly seen in costume jewelry. A foilbacked rhinestone whose foil has been damaged (often from water creeping ing) does not sparkle anymore and is said to be a "dead" stone, lowering the value of the piece. Before, modern, highly reflective cuts were developed, even diamonds were foilbacked.