925 Sterling Silver Natural Australian Boulder Opal Doublet Pendant Necklace | October Birthstone | Fine Gemstone Jewelry | Gift Jewelry Opal is the queen of gemstone, which is one of the most beautiful gemstones in the world. Every piece of opal is unique. Its optical effect is Play-of-Color, which shows a vivid play of iridescent color. The colors change when the stone is viewed with various angles. We only use natural opal (no synthetics) for our jewelry. This elegant pendant necklace is simp