Abstract
Pearls from the Lion’s Paw scallops Nodipecten (Lyropecten) Nodosus L. 1758 and Nodipecten (Lyropecten) subnodosus Sowerby 1835 are rare and have only recently come to the notice of the gemological community. They are non nacreous but differ in surface appearance and composition to other non nacreous pearls such as the conch and melo varieties. The surface appearance is comprised of a patchwork of cells with each cell being formed from three sub-cells. The orientation of these sub-cells and the low magnification fibrous appearance of structures within them give the scallop pearl a peculiar surface sheen. SG and Raman data indicate that the perfectly round 5.91ct scallop pearl described is composed in the main of calcite rather that being dominated by aragonite as is the case for the Melo and Conch pearls. In addition the chemistry, infrared, and UV/visible spectra for the 5.19ct scallop pearl are described. This data is compared with similar data from lion’s paw shells and detailed submicroscopic structures are described for the shells.