L’œil de Sainte-Lucie

Abstract

Highlighted by popular belief, the eye of Saint-Lucia is a biomineral, which is of undoubted gemological interest by its nature and through its use. As gastropod operculum of the species Bolma rugosa, its name is not protected and may have been used for other gastropod species. Calcareous opercula are showcased in jewelry on both their outer and inner sides. The latter features a logarithmic spiral pattern that can be found on opercula of various Turbininae species, and whose opening parameter seems constant for a given species.