Pearls are one of Mr Cox’s passions, having visited pearl farms in Japan and seen how they are produced. There are several different types of pearl, which can be confusing, so here are the main variations.
These occur in oysters without any intervention by man. These are now no longer fished commercially.
In 1904, the Japanese discovered that if you insert a bead into an oyster and return it to the sea, it would coat the bead with pearl nacre – thus the cultured pearl was born. Grown in Akoya oysters, these range in size from 3mm to 10mm.
Pearls have been found in freshwater mussels, and again the Japanese discovered how these could be kept and induced to make pearls. For many years, the results were disappointing, with very irregular pearls, but with improved breeding of mussels and care, beautiful pearls in sizes from 3mm to 13mm are produced. Freshwater cultured pearl farming has expanded greatly in China.
These are much bigger pearls – from 10mm to 16mm – usually silver in colour, but occasionally golden, and are produced by silver-lipped oysters mainly in Australian waters.
Produced in black-lipped oysters originally in the Tahitian archipelago, these range in size from 8mm to 14mm and vary in colour from blue-grey, through grey to black.
There are other types of pearl, as many molluscs can produce them. We have even seen a steel blue one, brought in by a customer who found it in a mussel from the North Sea!