Shop SWIRLSSilver and Black Opal Swirl Pendant. 337-BO-P Silver and Black Opal Swirl Pendant. 337-BO-P € 145.00 Silver and Black Opal Pendant - Opal size 3mm. Swirl disc measures approximately 12mm diameter. Each piece from our studio is hallmarked in Dublin Castle by the Irish Assay Office and will be carefully packaged in a custom presentation box. All our pieces are especially handcrafted to order in our Dublin Studio and take from 4-6 weeks to dispatch. Deirdre O'Donnell Contemporary Jewellery