Tanzanite and Diamond Platinum Ring, 4.50 ct Bezel-Set Tanzanite, Circa 1970s

A 4.50 carat round brilliant tanzanite sits bezel-set at the center of this platinum ring, its violet-blue color shifting toward a deeper blue or a warmer purple depending on the angle of light; the pleochroism that makes tanzanite distinct from sapphire. Sixty-six round brilliant diamonds, F-G color and VS-1 clarity, radiate outward from the bezel in tapering rows that follow the ring's domed, fluted profile, each row separated by a raised platinum rib. The fluted, sunburst-like setting draws the eye outward from the tanzanite rather than framing it in a flat halo, giving the ring real dimensional movement. Stamped "Irid Plat" inside the shank, indicating an iridium-platinum alloy standard for the period. At 18 grams, this is a substantial ring with real weight and presence, consistent with the bold, gem-forward style tanzanite jewelry took on soon after the stone's introduction in the late 1960s. Excellent condition, no visible wear.