Contemporary 18 Carat Yellow Gold Mint Green Tourmaline and Diamond 18 Karat Yellow Gold Tourmaline Diamond Ring For Sale at 1stDibs Tourmaline, Diamond and 18k Yellow Gold Vintage Ring For Sale at 1stDibs Tourmaline, Diamond and 18k Yellow Gold Vintage Ring at 1stDibs. Proud to be Family Run Green Handmade Our goldsmith created this chunky piece with a signet ring style in mind. A large 12. 62ct cabochon cut green tourmaline takes centre stage, above a ring of 36 castle set brilliant cut diamonds. The 18ct yellow and white gold ring was designed and handcrafted in our onsite workshop. Specifications: Metal: 18ct Yellow and White Gold Stone weight: 12. 62ct green tourmaline & 0. 30ct diamonds Colour: G H Clarity: SI Current size: UK O Related Product: 18ct Yellow and White Gold 5. 35ct Black Opal and Diamond Cluster Ring