These pearls are natural calcareous concretions without a nacreous layer structure formed by the sea snail species Strombus gigas (pink or queen conch) and Pleuroploca gigantea (horse conch). The most common colours of queen conch pearls are pink and white and those of horse conch, beige and brown. Conch pearls are easily recognisable due to their characteristic flame structure visible on the surface and their porcelain-like lustre.
