Constructed from solid Sterling Silver, this pair of earrings highlights a pair of Natural Boulder Opals originating from Australia and marked with the 925 stamp. Boulder Opal is classified as a Natural Opal Type 2 by the Opal industry, which implies that it is naturally attached to a host rock that has a distinct chemical composition. Genuine Natural Australian Boulder Opal consists of hydrated amorphous concretions of SiO2nH2O silica, which are formed from silicon dioxide molecules arranged in closely packed planes that fill the crevices of Boulder Opal ironstone. This form of Opal is only found in isolated regions of Queensland, Australia and is a rare resource that has supposedly increased in value by up to 15% per year. The pendant is guaranteed to be free of any artificial coloring or dyes. All Australian Opal Cutters Jewellery and Loose Opal items are covered by our international warranty. Please send us an note when you check out if you would like to add any modifications or changes or have a specific colour requirement for your Opal. On request and at an additional charge we are able to change or upgrade your Opal (or change the design) of any item that we offer. The item shown online may not exactly reflect the item you receive as Opals have a living play of colour that can be difficult to capture on camera.