Boulder Opal Solid Pendant, Blue Green Flash Pattern. Boulder Opal is made of two layers. A natural formation of Ironstone formed with Opal. Opal color moves across the stone as the stone moves.Photo's are of the Opal item available. This item is in the category "Jewellery & Watches\Fine Jewellery\Necklaces & Pendants". The seller is "jasmine-opals_australianjewelleryandgemstones" and is located in this country: AU. This item can be shipped worldwide.