A Doublet Opal is a layer of genuine Natural Crystal Opal with a layer of Australian Boulder Opal "potch" (or ironstone). The two layers have adhered with silica-based adherents that have the same coefficient of expansion as the Opal so that the layers do not delaminate over time. Opal Doublets are guaranteed for life against delamination. Doublet Opal Earrings are rare and valuable as the matching colors are almost impossible to replicate in the more expensive solid Opal. All Sterling Silver and Solid Gold rings can be resized. Please see this article if you need help in working out what your finger size is. https://australianopalcutters.com/blogs/news/ring-size-what-you-need-to-know if you would like to book a resize service then please select this link and book a resize for $50 https://australianopalcutters.com/products/workshop-resize-ring?keyword=re Stainless steel rings are not able to be resized so please email us if you are unsure about the size of any stainless steel ring you see online.