Very Fine and Rare Large Conch Pearl, Strombus gigas or "Queen Conch", Caribbean Sea. Photo Bonhams.

A conch is one of a number of different species of medium-sized to large saltwater snails and their shells. True conchs are marine gastropod mollusks in the family Strombidae, and the most well known species is the Strombus gigas or "Queen Conch". The pearls they produce are calcareous concretions—that is they are non-nacreous and are made up of calcium carbonate (rather than aragonite which is the composition of nacreous pearls).

Several thousand snails would have to be found in order to recover a pearl as fine—and as large—as this one. Its color is even—a true rose pink hue—and the luster is porcellaneous. But these factors are matched by the quality of its flame pattern iridescence—it consistently and evenly covers the entire pearl appearing to shimmer above its surface. Bonhams is pleased to offer this world-class, gem conch pearl. Weighing approximately 12.71 carats and measuring 14.0 x 10.6 mm. Estimate US$ 70,000 - 90,000 (€51,000 - 65,000)

Bonhams. GEMS, MINERALS, LAPIDARY WORKS OF ART AND NATURAL HISTORY. Los Angeles, 20 May 2014 10:00 PDT - www.bonhams.com