Colour & Luster | Shapes & Sizes | Grade | Sustainable Farming
Colour & Luster
Tahitian pearls, also known as Black South Sea Pearls come from the black lip oyster (Pinctada Margaritifera) grown in the region of French Polynesia. Although Tahitian Pearls are termed black, they have an incredibly wide array of iridescent colours ranging from whites, greys, silvers through too dark black, with classic secondary undertones of green, gold, purple, rose and blue. The colours of Tahitian Pearls are completely natural, unlike black Akoya pearls or black freshwater pearls, which are dyed or irradiated to achieve their darkness.
Pearls are categorized on their ability to glow (reflect or refract light) when illuminated with natural light. This is known as Luster. Luster can be categorized from poor to very high. Luster is a significant factor in determining the quality of a pearl.
Shapes & Sizes
Tahitian pearls are available in various sizes ranging from 8-20mm. The largest pearls are the rarest type.
Types of Tahitian pearl shapes include:
- Round -This refers to perfectly round and symmetrical shaped pearls.
- Semi-round - These are almost the same as round pearls with slight variance in diameter. The variance may be slightly noticeable by the naked eye.
- Baroques - These pearls have no axis of symmetry. Baroque pearls can range from being a round pearl with a bump, to wavy and bulbous shapes.
- Semi-baroque - This includes: drop, buttons, ovals and other variations in shape.
- Circled pearls - This type of pearl has concentric rings etched into the pearls form.
These are a valuable by-product of pearl culture. Keshi pearls are often small and generally have a large degree of variance in shape. Keshi's can however grow to larger sizes and may also be found in round shapes. They consist entirely of nacre and can come in a variety of colours.
The Tahitian system of pearl grading is broken down into the A-D categories. This system assess pearls in the following way:
A Grade - The pearls surface should be 90% clean of any imperfections with very high luster. There should be no deep imperfections.
B Grade - The pearls surface should be greater than 70% perfect with high luster. Small minor imperfections may be visible
C Grade - Must have decent luster with 50% of the pearls surface clear of imperfections. The remainder of the surface may have small imperfections.
D Grade -The Pearls will show flaws and imperfections on 60% of the surface. Deeper inclusions may also be present. The pearls luster is variable.
Please Note: A second system of grading exists defined by A through AAA. This system is used more frequently by those who sell various types of pearls such as Tahitian, Akoya and South Sea Pearls.
Sustainable Pearl Farming
Cultured pearl farming is a vital source of income and has significantly contributed to the economic development of a large number of communities in the French Polynesia region. Pearls still remain the largest export of French Polynesia in 2018 (OEC, 2018).
Marine cultured pearl farming does not harm the environment if adequate management practices are implemented. Cultured pearl farming can be regarded as a sustainable element in improving not only coastal livelihoods, but also fostering environmental conservation.
Responsible pearl farming techniques reduce the impact of pearl farming on the ecosystem. A practice utilized by some farms includes an ecologically sound technique to clean pearl oysters. This technique utilizes the local reef fish to remove biofouling from oysters, an operation that is required to be carried out every couple of weeks to ensure the healthy growth of oysters. The biofouling offers food to the reef fish and reduces the need for mechanized technology like high-pressure jet cleaning of oysters. This technique not only protects reef fish but increases the abundance of them.
Conserving the tropical ecosystem in which pearl oysters thrive is a priority if global biodiversity loss is to be reduced. Pearls reflect the health of our oceans, and therefore a healthy ecosystem is required to grow such beautiful pearls.
How Pearl Farming Works
The oysters swim freely in the lagoon for approximately 3 weeks. The shells then become too heavy so the oyster searches and attaches to a collector. Artificial collectors are set out during strategic times of the year that correspond with changes in the season to offer ideal places for the oysters to seek refuge and mature. After approximately two and a half years the oysters are large enough to start producing pearls.
The next step is the grafting procedure which starts with transplanting a small mantle (the organ that secretes the oyster’s iridescent shell) from one oyster to another. The nucleus is then inserted. This is a small ball in which the pearl grows around. This is an important step and helps determines the quality of the pearl.
Nuclei utilized by our supplier are made of mother of pearl (MOP), a natural product of the Pinctada margaritifera oysters or their Pinctada maxima cousins.
Following the grafting process, the oysters are placed inside baskets and suspended on long lines in the lagoons. The pearls grow in the oysters for around a year and a half. Every few months the baskets are cleaned by hanging them near the reef where fish feed and clean them naturally. Alternatively they can be scraped by hand with cleavers. Upon appropriate time in the lagoon the oysters are then removed, and their pearls are gently extracted.
Learn More about pearls from Sustainable Pearls.org
Shop our Tahitian pearl jewellery here.