78.71 carats Melo-Pearl and Diamond Ring. Estimate  750,000 — 850,000 HKD (89,042 - 100,914 EUR). Unsold. Photo Sotheby's

Set with a melo-pearl weighing 78.71 carats, to a stylized mount pavé-set with circular-cut and rose-cut diamonds together weighing approximately 3.40 carats, mounted in 18 karat white gold. Ring size: 5¾ 

Melo Pearls

Melo pearls are considered one of the rarest and most precious pearls in the world. Unlike other pearls that are produced from oysters or mollusks, melo pearls are produced by melo melo marine snails and contain no nacre. Because of the pearl’s extreme rarity and increased interest, many attempts by researchers have been made to cultivate these extremely rare pearls; however, no successes have been made, thus every melo pearl is naturally created. They can range from a light tan to dark brown colour- orange being the most desirable. Although melo pearls do not have the translucency of regular oyster pearls, they contain a flame structure that creates a unique and beautiful iridescence.

Sotheby's. Magnificent Jewels & Jadeite, Hong Kong, 06 Apr 2015