size: 5 weight: 5.82 grams material: platinum gemstones: natural unheated sapphire 1.40ct natural diamonds: F-G, VS clarity, 0.43ctw Notes from the Curator This platinum ring centres an oval sapphire of 1.40 carats certified as natural and unheated—a distinction that places it within the rarest five per cent of the market. Nearly 95% of sapphires sold today undergo heat treatment, a stable and widely accepted enhancement that intensifies colour and clarity, but unheated examples can command two to three times the price of heated counterparts of equivalent quality. The oval cut maximises brilliance and weight retention, while the round brilliant halo and tapered baguette diamond shoulders recall the geometric precision of mid-century design. Platinum's density—the heaviest of the noble metals—offers both structural security and a cool lustre that complements the sapphire's saturation without competing. An unheated stone carries its geological history intact, with growth characteristics and inclusions that tell the story of where it formed, whereas heat can erase these diagnostic markers. The hallmark confirms platinum content, and the total diamond weight of 0.43 carats in near-colourless F–G grades amplifies the central stone without diluting its presence.