Crafted from solid Sterling Silver, these earrings showcase a pair of Natural Boulder Opals hailing from Australia and stamped with 925. Boulder Opal falls under the category of Natural Opal Type 2 in the Opal industry, indicating that it occurs naturally attached to a host rock with a distinct chemical composition. Genuine Natural Australian Boulder Opal comprises hydrated amorphous concretions of SiO2nH2O silica, formed from silicon dioxide molecules arranged in closely packed planes filling the crevices of Boulder Opal ironstone. This type of Opal is a scarce resource and is exclusively found in select regions of Queensland, Australia. Its value is said to have appreciated by up to 15% annually. The pendant is certified 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.