Pearls

The Pearl is a more or less regular spherical structure, made of calcium carbonate deposited in concentric layers from the living tissues of some molluscs.
It is formed when a foreign body enters the soft mantle of the mollusc, causing it to irritate the tissues. As a reaction to this irritation, the animal covers the foreign body with thin concentric layers of nacre or mother-of-pearl, which over time will lead to the formation of a pearl

The pearls are divided into 2 types:
Natural Pearls in which the foreign body that generates the pearl accidentally penetrates inside the mollusc
Cultivated Pearls in which the foreign body is inserted by man.

Today 99% of the market is made up of cultured pearls and the few marketed natural pearls are randomly found by fishermen.

THE CULTURED PEARLS

After the grafting of the nucleus, the hand of Man steps aside and the oysters are placed inside cages suspended in sheltered bays or basins rich in nutrients. For the following months, the molluscs are periodically turned upside down to favor the growth of regular pearls and constantly cleaned up from the incrustations to prevent the attack of pests.
Furthermore, to ensure the best possible conditions, they are constantly monitored by specialized technicians who check the water temperature and the supply conditions on a daily basis.
Despite these treatments, half of the oysters will die due to natural events, while the remaining 20% ​​will be commercially exploitable. In fact, most of the pearls will be too imperfect to be used in jewelry.

Akoya or Japanese pearls
Oyster: Pinctada fucata martensii

Cultivation:
Oyster is grown in nurseries in sea water for a period of 10 to 24 months. It is a non-productive perliferous mollusc that accepts the grafting of only one nucleus at a time and, in the course of its life, bears only one cultivation. It is a small animal, capable of producing cultivated pearls with a tendentially small diameter, but with exceptional characteristics.
The main producer of this variety of pearls is obviously Japan, but there are also cultivations in China, Vietnam, Korea and Thailand.

Features:
The dimensions of Akoya pearls range from 2mm to 10mm and their main characteristic is sphericity. In fact, the percentage of spherical pearls is close to 80% of the harvest.
In addition, the surface of these pearls has few defects and is characterized by a noticeable gloss, with a base color white but which may have gray reflections, silver rose or champagne.
The characteristics of Shape, Size, Color, Shine and Grade of homogeneity therefore become parameters of classification of the pearls that allow them to be divided into categories and simplify their marketing.

Curiosity:
In the raw state, Akoya pearls are generally cream, yellow or green. Following a washing carried out with particular substances, of which each manufacturing company keeps the technique secretly, they are bleached and take on silvery white or champagne pink, becoming more homogeneous in color.

South Sea or Australian pearls
Oyster: Pinctada Maxima

Cultivation:
The first phase of the cultivation of South Sea pearls is fishing, in fact the Pinctada Maxima is not bred but rather fished by divers, as it lives at depths that can reach 100m. Afterwards the molluscs are cleaned and selected and only then are they grafted.
The Pinctada Maxima is a very delicate organism and its cultivation is characterized by a high percentage of mortality, which comes to touch even 80% of the specimens.
The cultivation period lasts about 2 years.
The harvest takes place in the winter months because with the lower temperature the secretion of pearling is slower and more uniform and this leads to a greater gloss

Features:
The South Sea Pearls are easily identifiable by their size which generally ranges between 9 and 17 mm. They have a spherical nucleus of mother-of-pearl covered by a layer of pearling sufficiently thick and compact that in the 15mm pearls reaches about 4mm.
From the chromatic point of view the South Seas Pearls are distinguished according to the mollusc that produces them. In fact there are two varieties of Pinctada Maxima, the first called silver-plated oyster produces light pearls ranging from silvery white to rosy white, the second variety called oyster with golden lips produces pearls with champagne or light yellow reflections.
These pearls, unlike Akoya pearls, also have an exceptional variety of shapes that allows their classification in:
Round (perfectly spherical)
Round seeds (almost spherical)
Oval (more or less oval elongated shape)
button (spherical crushed)
Baroque (irregular)

Place of cultivation: The Pearls of the South Seas are mainly cultivated in Australia and precisely in the northwest part of the continent in a remote area that is about 200km from the major urban center and therefore does not suffer from effects of pollution.The other producing countries, but with decidedly lower quotas, are Indonesia, the Philippines and Vietnam.

Tahiti pearls
Oyster: Pinctada Margaritifera

Culture:
Unlike the Australians, the cultivation process starts from the collection of oyster larvae in the center of the lagoons making them fix on supports appropriately laid. The young oysters are then harvested when they reach the size of about 2 cm and after a selection they are bred in the “nursery” for about 3 years until they reach the size necessary to implant the mother-of-pearl nucleus. Subsequently, the oysters are placed back in the lagoon for not less than 18 months. Despite the care and attention, less than half of the molluscs will produce one or, rarely, two pearls.

Characteristics:
The main characteristic of the Tahiti Pearls is definitely the color, they are in fact the only dark pearls and present a kaleidoscope of colors that for various shades of gray it goes up to oil green or blue / violet. The size of these pearls is similar to those of Australian pearls and ranges from 8 to 16mm. Even the Tahiti Pearls have a remarkable variety of shapes that is very similar to that of the Australians.

Cultivation field:
As can be seen from the name of these pearls they are cultivated on the island of Tahiti and more generally in the archipelagos of Polynesia.

 

Fresh water pearls
Oyster: Hyriopsis Cumenigii

Culture:
The cultivated pearls of fresh water are born thanks to a technique different from that used for the cultivation of salt water pearls. In fact, in order to trigger the production of Fresh Water pearls, a fragment of the epithelium of another oyster is inserted into the shell of the oyster, not a nucleus of mother-of-pearl like the other varieties of cultured pearls. Inside the grafted mantle an anucleate pearl will form, that is without a core and completely made up of layers of pearls. Unlike sea molluscs, freshwater ones, after receiving the first plant, can continue to produce pearls for two or three consecutive cycles.

Features:
The main feature of Fresh Water pearls is the unlimited variety of shapes, the most common are the irregular ones . The round shape instead is much less frequent, because, since there is no core, it is more difficult to obtain a perfectly spherical growth. The size of Fresh Water beads is on average higher than the Akoya and ranges from 2 to 13mm, while for the colors come in a variety that goes from white to purple through the shades of pink.Use of cultivation: the freshwater pearls are produced mainly in China, but there are also productions in Japan and the United States.