The most rare pearl in the world is the Melo Melo, which is produced by a sea snail and not an oyster or a mollusk. The Melo Melo differs in appearance compared to a classic pearl, having a shimmery surface with swirling patterns in the light.

Perfectly round pearls with a smooth surface and a rich, even color are the rarest and most valuable. Pearls that are misshapen, have blemishes, or lack luster are less rare and therefore less valuable.

The Melo Melo Pearl is one of the most highly prized pearls on the planet. Touted as the rarest of all pearls by Town & Country magazine, the Melo Melo pearl is a non-nacreous pearl that forms in the marine gastropod known as Volutidae – a large sea snail commonly called “melo melo.”

Melo pearls are becoming increasingly popular. Town & Country called the stone "the rarest pearl of all" after Tiffany & Co used a 95-carat Melo pearl stone as part of its 2021 'Colors of Nature' collection.