Tanzanite and Diamond Cluster Ring For Sale at 1stDibs Tanzanite and Diamond Cluster Ring For Sale at 1stDibs Gold Tanzanite & Diamond Cluster Ring Rings from Cavendish Jewellers Tanzanite Diamond Ring of Square Cluster Design For Sale at 1stDibs Lot 19 A tanzanite and diamond square cluster ring. An 18ct gold tanzanite and diamond cluster ring. Jun 06, 2013. An elegant cluster ring that features to the centre a rectangular tanzanite gemstone that measures 6x4mm (est 0. 50 carats) AAA colour. Complimented by an outer halo of sixteen small white diamonds , 1. 5mm each. Further seven diamonds per shoulder. Total diamond content estimated at 0. 45 carats. Colour i j, clarity Si. Head measures 9x8mm, depth 3. 4mm, weight 3. 6grams. UK hallmarks, no date letter, probably 2000 1010, all 18 carat white gold. Size O, we can resize free of charge.