Modiolus philippinarum (commonly referred to as the Philipine Horse Mussel). These pearls were collected over decades from animals found on Indo-Pacific shorelines. The pearls in this 21" long, expertly created strand range in size from 1.5-6.2mm and the total weight of the strand (with out a clasp) is 41 cts. The natural deep purple color being the most sought after from this species.. this strand is a shining example of both patience and expert drilling. We are happy to discuss clasp ideas for this piece at the time of purchase. ID#OT36000-02-23x9