Conchs are large marine gastropods that grow thick and heavy shells with a high spire, a long siphonal canal, and a flared outer lip that widens as the animal matures. Most species are herbivores, feeding on algae and seagrass. The family Strombidae, known as the true conchs, includes more than 60 species. Only a few are known to produce valuable pearls.

The most important of these is the Queen Conch, Lobatus gigas, formerly known as Strombus gigas. The shell is responsible for nearly all of the conch pearls used in jewelry, and is native to the Caribbean region. It's commonly found in shallow coastal waters from southern Florida and the Bahamas to Mexico, Belize, and Trinidad. Queen conchs prefer warm, sandy sea beds that are easily accessible, making them an important local source of both food and shell.

The meat of the conch is a dietary staple in many Caribbean countries and a major export. Pearls, on the other hand, are discovered purely by chance. Fewer than one in 10,000 shells contains a pearl, and only a tiny fraction of those are of gem quality. Because the shells are heavy, they are often discarded at sea during harvesting. Most pearls are found during the routine cleaning and processing of the meat, not by deliberate searching. This makes every gem-quality conch pearl an exceptionally rare find.

While Lobatus gigas is the primary species known to produce fine pearls, a few others occasionally produce them. Pearls produced by the Horse Conch (Triplofusus giganteus) and the Emperor Helmet (Cassis madagascariensis) are even rarer, but tend to be cream, orange, or brown in color and considered less valuable.

Live Queen Conch (Lobatus gigas) held for research. While prized for its meat and shell, the pearls it occasionally produces are discovered purely by chance.