Necklace Collection :
Antique Opal and Emerald and Seed Pearl Choker Necklace and Bracelet, Late 19th Century. Opals from Dubnik, Slovakia. Prior to the discovery of opals in Australia, the only known locality for opals in the world, was a volcanic deposit situated in Dubnik, Slovakia. In fact, nowhere has opal been mined as long as it had been in this region. Sources dating back to pre-Roman times mention opals from this region.