Centring on a cushion-shaped chrome tourmaline weighing 4.25 carats, framed by blue sapphire surround within a blue sapphire outer border alternated by trapeze-cut diamonds, to diamond-set bifurcated shank. Mounted in 18 karat yellow gold. Ring size: 6 3/4. Chrome tourmaline is coloured by chromium and vanadium, this rare tourmaline displays a rich, intense green that rivals the very finest emerald and tsavorite garnet. It was first mined in Tanzania in the 1960's and is not often available. Generally chrome tourmaline can only be found in small sizes, gem quality stones over 2.50 carats are considered very rare.