A tiny thistle gets a bright opal-blue update. Daria Salus pairs sterling silver with kiln-fired enamel for these nature-inspired earrings, handmade in the Bay Area. The opal blue gives the small thistle motif a cool, luminous finish. A closer look at Silver and Opal Blue Earrings - Thistle shows off copper, enamel, glass, and sterling silver and the earring shape without piling on extra fuss.