Cook Islands Pearl Selection Guide

Black pearls are named after the famous shell from which they come – Pinctada Margaritifera – the black-lipped mother of pearl shell. One of the world's rarest and most exquisite pearls, they are treasured for their lustrous beauty, and highly sought after for jewellery. A revival of their popularity in the world of fashion has seen a thriving industry develop in the Cooks.

Pearl cultivation began in the Cook Islands in the early 1970s, and commerical farming was established by the mid-1980s. Today, the turquoise lagoons of Manihiki and Penrhyn in the northern group form the heart of the Cook Islands pearl industry. There are dozens of successful farms – mostly family-owned ventures harvesting anywhere from 1,000-60,000 pearls annually, and contributing $US4.5 million a year to the economy.

Selecting a Pearl
The grade and value of a black pearl is determined by its overall quality. In addition to their colour, pearls are judged by their size, shape, lustre and surface perfection. Before you buy, talk to retailers and those in the industry to help you select your pearls. The Pearl Guild publishes a useful guide highlighting these points, which is freely available at all Guild outlets. This basic guide will help you make your selection.

Size
Cook Island Pearl SizesIn the Cook Islands, Pinctada Margaritifera produces pearls with an average diameter of 10-11mm. While sizes can reach 18mm, pearls of 13mm or more are rare and represent a small percentage of any harvest. Most pearls range in diameter from 8-12mm.

LustreCook Island Pearl Lustre
This term refers to the brilliance and reflection of light on the surface of the pearl. Warm and alluring, it is a virtue that combines the quantum nature of light and the subjective views of the beholder.

Colour 
Cook Island Pearl ColoursThe colour of the pearl comes directly from the mantle of the shell, which secretes the nacre (mother of pearl) required to develop it. The basic black or dark grey colour of the Cook Islands cultured pearl combines with a multitude of hues from its host shell, ranging through iridescent green, ocean and peacock blues, pink/rose, golden, platinum or rainbow highlights. All colours have their special qualities and individual taste should be the criteria for judging them.

Shape
Cook Island Pearl ShapesThe shape of a pearl depends very much on the shell and the whims of nature. In its effort to rid itself of the irritating nucleus, a shell often turns and moves the object of its discomfort, so creating many different shapes. Pearl shapes include round, semi-round, drop, baroque, circle and button. The closer a pearl is to being round, the more expensive it becomes.

Surface PerfectionCook Island Pearl Surface Perfection
Fine pearls will have an absence of surface marks or depressions. The surface quality is judged by the position and number of blemishes, and ranges from marked to exceptional. As with any of nature's creations, it is unusual to find a pearl totally without these markings. Instead, they should be considered as evidence of nature's art.