''A pearl is always appropriate''

Pearl in general

Pearl is an organic product and therefore we call it an organic gemstone. Organic because it is formed by molluscs like mussels (freshwater) and oysters (saltwater). This can happen naturally or through cultivation. Therefore, pearls can be distinguished in natural pearls and cultured pearls. Natural pearls are very rare and their extraction is not very environmentally aware. Also, the quality of cultured pearls can differ a lot. With cultured pearls, people have an influence on the environment in which the shells live and on the quality of the pearls that are formed. Cultivation of pearls began in the early 1900s in Japan. There are four different types of pearls; freshwater pearls, akoya pearls, Tahitian pearls and South Sea pearls. The most common of these is the freshwater pearl and it is also the most commonly used in jewellery. Originally, pearls were extracted naturally in several European countries. Nowadays this is limited to Latvia and Scotland. Apart from European countries, natural pearls also come from North America. Japan and especially China have become the largest producers of cultured pearls. The value of pearls is assessed based on four different factors: lustre, colour, surface area and shape. In addition, the presence of any irregularities and the thickness of the mother-of-pearl layer is also taken into consideration.

The four different types of pearls

AKOYA: white, small pearls
The Akoya is the best known saltwater pearl. If we translate akoya from Japanese we get ‘my child’, which in the case of this pearl is understood to mean ‘children of the sea’. Characteristic for the akoya is that this pearl is rather small; never larger than 10 mm. This is because the shell in which these pearls grow never has a diameter larger than 9 cm. It takes an average of two to five years to grow an akoya pearl, depending on the desired size. In addition, it is typical that this pearl occurs in different shades of white; ivory, cream or with a soft pink or soft yellow sheen. There are even champagne and lilac coloured pearls. Nowadays, black akoya pearls are also cultured artificially. This is done using laser technology. The formation of akoya pearls is done with the help of lime, which causes many different layers of mother-of-pearl to be put on top of each other. These layers eventually give the pearl its extreme lustre, which determines its quality. The akoya pearl is always quite small and perfectly round and for this reason it is often used in classic pearl necklaces. Tokichi Nishikawa and Tatsuhei Mise have developed a technique to cultivate the perfect round pearl using a special needle that Mise developed for this purpose. Most of the rights to make the perfectly round akoya pearl now lie with the Mikimoto Pearl Company. Akoya are beautiful, small, classic pearls.

TAHITI: Grey/black pearls, with a coloured glow that can vary from pearl to pearl (similar to the colour and glow of oil).
The Tahitian pearl is the only pearl that is naturally black in colour. The colours of these pearls can range from green or bronze to deep purple or black. The inside of the oyster determines the colour of the pearl. Tahitian pearls are formed in fairly large oysters called ‘black lipped oysters’. These oysters can be 30 cm in diameter and weigh up to 5 kg. This ensures that the pearls from these oysters are quite large. They can vary in size from 8 mm to 20 mm. Not only the pearls from these oysters, but also the mother-of-pearl from the shell was (especially in the past) used for e.g. jewellery or decoration and it was even used to pay with. Nowadays, the mother-of-pearl from these shells is still used in jewellery.

As with akoya pearls, the lustre and shape determine the quality of the pearls. In the case of Tahiti pearls, the cultivation process can be disturbed by, for instance, sand grains entering the pearl. This may cause certain irregularities in the surface of the pearl. Although this detracts from the value of the pearl, these unique ‘baroque pearls’, as they are called, are very popular and have the same pure lustre as perfectly formed Tahitian pearls. Tahiti pearls are mined off the island of Tahiti (hence the name) as this is where the oyster species originated. In French Polynesia, Tahitian pearls are also found, but the export of these is quite strict; the pearls must have a minimum nacre (thickness of the mother-of-pearl) of 0.8 mm. Those that do not meet this requirement cannot be exported and are destroyed.

SOUTHWATER: White pearls, various shapes
Freshwater pearls are cultured in China and Japan, and on a smaller scale in Indonesia and America. Freshwater pearls form in mussels. Cultivation involves opening the mussel and inserting pieces of epithelial tissue into the soft parts of the mussel. A pearl is then formed in the mussel in response to the inserted epithelial tissue. The formation of a freshwater pearl can take a minimum of six months and a maximum of ten years. Unlike saltwater pearls, freshwater pearls do not have a nucleus. This ensures that the nacre does not form around a fixed point and therefore there are few freshwater pearls with a perfectly round shape. The shape of freshwater pearls is often described as potato or oval and for example rice or bouton pearls. In the past, people were not keen on making jewellery with pearls of unusual shapes. Nowadays this is seen as a challenge by many designers and these shapes are therefore very popular. Apart from shapes, freshwater pearls are selected on colour and size. The colours of freshwater pearls can vary. They come in white, salmon pink, lavender pink, grey and peach orange, for example.

The value of freshwater pearls may be lower than that of saltwater pearls, because the shells in which freshwater pearls form are cheaper to purchase and they are less susceptible to disease. Also, the formation of freshwater pearls takes a relatively short time.

SOUTH SEA: large pearls, usually white, sometimes gold
South Sea pearls are found along the coast of Australia and in the Philippines and Indonesia. Mainly white South Sea pearls come from Australia. Pearls with a more golden lustre often come from the Philippines or Indonesia. Between white and gold, the pearls come in champagne tints and various gold colours. South Sea pearls are fairly large; the oysters in which they form can be up to 30 cm in diameter. As a result, the size of the pearl can reach up to 20 mm. This particular oyster is very sensitive and very susceptible to disease. The cultivation area is also rare and therefore these particular pearls are very expensive.