Worbla is a cosplayers best friend.
The ring with two blue stones was bought on etsy from a Canadian 3d printer, there are also metallic copies from China on ebay. For the other ring I didn't have a clear reference until last weekend when someone posted a photo, I couldn't find the reference again though so had to make it from memory. The size might be off, but until there are more available reference photos it will have to do. It's made with fimo clay, similar to sculpy, and painted with acrylic paint in blue and brass.
Overall I am really happy with the jewellery and the brass paint turned out to be really good. I'm surprised that it actually is so shiny and metallic looking even if it's just paint.
Finally I couldn't help myself, so after having struggled to get the wig into a reasonable shape I wanted to do a full costume test. So ignore my bleary face, and the frizzy wig, but I am getting there.