A Brief Study of Three Reported "Coconut Pearl" from Southeast Asia

We investigated three so-called "coconut pearls" loaned to us by a private collector. The white, roundish "pearls" possessed peculiar longitudinal surface grooves, and on one side they showed one or three small bulges. The samples were found to consist of polycrystalline aragonite, as shown by Raman spectroscopy, supported by SG measurements and their reaction to hydrochloric acid. They showed a parallel-layered structure that is consistent with shell material. The surface grooves showed evidence of filing, and it was obvious that the samples had been manually shaped. Based on the thickness of the shell that must have been used for making these imitations, and the similar structures seen in Tridacna shell material, we infer that they were manufactured from giant clam shell. There are no indications to suggest the samples actually derived from a coconut-related origin.