Diane Kordas 18-Karat Rose Gold Cosmos Earring with Prasiolite and White Diamonds. Diane Kordas creates fine jewelry for women who want classic pieces with a modern edge. Part of the \'Cosmos\' collection, this earring is handmade from 18-karat rose gold that\'s set with 0.06-carats of glistening diamonds and a beautiful 0.65-carat prasiolite. Post fastening for pierced ears. Sold as a single earring.