Observations on pearls reportedly from the Pinnidae family (Pen pearls)

Abstract

Pearls of all kinds have been used for decorative purposes throughout history. The majority of these have been nacreous, yet certain non-nacreous pearls have also been sought by connoisseurs. Pinna (pen) pearls fall into the latter group. The nature of their non-nacreous structure often results in cracking, and because of stability concerns they are very rarely used in jewelry. Nineteen of the 22 samples from this study, reportedly from Pinnidae family mollusks, show similarities in color as well as external and internal structure. Raman, photoluminescence, and UV-Vis-NIR spectroscopic results are discussed, along with the internal characteristics of pearls likely produced by this mollusk.