Conch "pearls" are calcareous concretions
produced by the Queen conch molliisk,
Strombus gigas, which is found in various
areas of the Caribbean. Although conch
"pearls" occur in a range of colors, the
pink are usually the most desirable.
"Pearls" over 10 ct are rare, but they have
been observed as large as 45 ct. They
sometimes exhibit a porcelain-like luster
and an unusual characteristic called
flame structure, which made pink conch
"pearls" quite popular in jewelry at the
turn of the last century. This article reviews
the history of the conch "pearl,"
discusses S. gigas and its fisheries, and examines
the gemologcal properties and
other characteristics of this attractive material