Very important information!!! We support for 3rd part gemstone and metal verification check!!! Before you buy it. Please be aware. We only use natural, genuine Australia blue opal and Genuine 750 Gold/18K gold. I do leather goods design, but Blue Opal is my personal love, I have worked with local artisans here made customized opal earrings,rings and necklaces for years. Opal stone are genuine/natural gemstone from Australia, (not coating opal) 4mm*6mm each earrings 750 gold. To keep the value of so unique creatures, we only use best material and real gold. our stone and metal are only genuine natural, not COATING...