Exceptional non-nacreous pearls and pearl jewellery

Over the past few months, we have again analysed a number of outstanding, historic, or gemmologically interesting pearls. These include natural pearls from gastropods and non-nacreous shells (Figure 1). These pearls often consist of interwoven bundles of aragonite fibres, which result in patchy to spiky patterns poetically known in the trade as flame structures. 

The selection of recently tested non-nacreous pearls presented in Figure 1 includes a perfectly roundish purple pearl from the Lion Paw scallop (Nodipecten nodosus), an important pink Conch pearl (Aliger gigas, previously known as Strombus gigas), two brownish Horse Conch pearls (Triplofusus Giganteus), two large round Melo pearls (Melo melo) each of about 130 ct, and a pair of ear-pendants designed by Anna Hu with an orange and white non-nacreous pearl of excellent quality and matching drop-shape.