Cultivating Black Pearls

The delicate process of pearl cultivation begins with the seeding of oyster shells by a trained and experienced technician. In the Cook Islands technicians from Japan, China and Australia have been employed to carry out this exacting work and, over time, several Manihikians have also become highly skilled as technicians.

A nucleus made from the shell of a freshwater mussel is inserted deep into the oyster together with a sliver of mantle tissue cut from a donor shell. This tiny piece of mantle will determine the colour of nacre which forms around the nucleus to create the pearl. The optimum result is a faultless perfectly spherical pearl of iridescent colour and glowing lustre.

Shells seeded for the first time are placed into see through “catch bags” so that the farmer can be sure in the early stages that the oyster has not rejected the pearl. The shells are attached to ropes called chaplets that are then tied onto long lines suspended under water in the lagoon. It is on these lines that the oyster will remain for a minimum of 18 months secreting layers of nacre over the nuclei to form a pearl. The resulting pearl’s shape and qualities are revealed only when harvested therefore the growing conditions are critical to the health of the oyster and its ability to produce a high quality pearl.

Once harvested, all pearls need to be sorted according to size and shape and then graded to meet the quality standards established by the Cook Islands Pearl Authority.