Our Hallmark Stamp Our silver rings are 92.5% pure silver, and each band has a “925” sterling silver hallmark stamp on the inside of the band. Our hallmarking is done by the inestimable Irish Assay Office at Dublin Castle which guarantee every ring’s authenticity. Choose from our beautiful selection of Celtic sterling silver rings to add a timeless piece of jewelry to your collection, or to gift a beautiful piece to a friend or loved one. Browse our stunning and distinctive range of sterling silver Claddagh rings and other Claddagh jewelry online now.