This fabulous Paraiba petrol blue/green colour cabochon tourmaline is collet set in 22ct gold on a sand cast shank. Great for fiddling with! Solid Argentium (935) silver which is purer than standard sterling silver. Individually sand cast, the mould is destroyed during the casting process so each ring is unique. It has a sand cast and filed texture with a soft sheen finish. Hall marked by the Birmingham Assay Office.