IS THIS THE ONE?
ize, shape and quality are used as the benchmarks for grading black pearls and only those of Grade C and above qualify as Avaiki pearls.
There are three categories: spherical, symmetrical and non-symmetrical. Generally, spherical pearls are the most valued and include rounds and semi-rounds. Symmetrical shapes include circles, drops, ovals and buttons. The non-symmetrical are known as baroque and semi-baroque.
Many layers of nacre built up over time form a surface that is evaluated according to smoothness and the presence of imperfections. As pearls are created by living organisms, perfection is rare. Like our human skin, slight imperfections often occur in the form of marks, spots, ridges and colour inconsistencies.
In the Cook Islands, pearls tend to range on average between 10mm and 13mm, although very occasionally a pearl may reach 18mm. With the exception of the button shape, the size is determined by the measurement along its shortest axis and in whole millimetres to represent one size category.
A pearl’s lustre is the intense brightness created as light travels through the many layers of nacre and is reflected back to the eye. Evaluation depends on the degree of brightness, which is influenced by the thickness of the nacre. Orient is the iridescent, shimmering play of colour that occurs when the nacre is particularly thick and wellformed. Visible when the pearl is rotated, it too adds value to the pearl.
Black pearls come in a wide variety of shades that mirror the rainbow-like spectrum found in the mother-of-pearl shell. The darker hues of black, blue, green and brown are prominent, while lighter colours such as white, silver, grey and gold are also evident. Besides these body colours, higher-quality pearls reveal translucent overtones that appear over the pearl’s body colour and create intermediary shades such as aubergine, peacock green and lighter pastels. They also add depth and glow. Colours do not usually influence the grading of an individual pearl but certain rarer colours do attract higher prices.