Everything about pearls: a quick guide to what you need to know about one of the most beloved items in jewelery. And it is also considered the stone (though it is not) of June ♦
We have prepared a guide to reveal all the secrets of this mysterious oyster product. If you want to raise any doubt about the pearls, and perhaps evaluate the necklace you have in the drawer, keep reading this guide.
Pearl is a sphere but is not always perfect. It consists of calcium carbonate in crystalline form (aragonite). This substance forms as a deposit in concentric layers and is produced from molluscs (usually oysters).
The term pearl derives from the Latin word pernula, indicating the shell that contains it, and whose oblong oval shape reminded the ancient Romans, curiously, the thigh of the pig.
A pearl is formed when a foreign body, such as parasites or pieces of shells, stops in the shell cavity of the shell. To protect yourself, the molluscs cover it with a pearls. In this way, several layers of calcium are deposited which, in combination with other minerals, create pearls.
The nacre, or mother-of-pearl, is the natural substance that the molluscs secrete to protect themselves from irritants such as fragments of shells, parasites or foreign bodies grafted.
Contrary to what you think, a round pearl is rare (and, therefore, worth more). Usually, however, cultured pearls do not have symmetrical shapes. Although they may be very lustrous, they cost less than round pearls. Pearls that are not round can be created with special systems: to get them, a plastic fragment is inserted with the shape chosen, which the oyster will cover with the mother pearl. The result is that after years of waiting, the pearl that is born has the enlarged form of the initial fragment.
There are not only the white pearls, the most common ones. The rarest ones are pink, cream, dark purple, gray and black. But today with cultivation techniques you can also get pearls in green, blue, or orange shades. They are mainly used in jewelery.
Black pearls are the rarest. They can be Akoya (they are cultivated pearls that are produced by the Pinctada Fucata Martensii, better known as Oryka Akoya), from river, or Tahiti, the finest. They are also rare because oysters that create black pearls are much more delicate.
There are freshwater and saltwater pearls. The former are cultivated in lakes and rivers, the latter in the ocean and often in the lagoons. The most precious are the South Sea. But they are very widespread: they are found in the Persian Gulf and Red Sea, in the Indian Ocean, along the South Coast of India, Sri Lanka.
Mother-of-pearl, besides being used in the jewelery market, is today also used in cosmetics and even for the creation of some paints.
How to evaluate pearls
The quality is measured with the luster, that is, with the amount and quality of light reflected from the surface of the pearl. Obviously, the shine is high, the better the quality. How to do? Try: You must be able to see your reflection clearly on the surface of the pearl. If, however, you see nothing, it means that the pearl is too white and opaque, probably of medium or low quality.
Pearls classification is complicated: in fact, two different systems are in use. AAA-A and A-D (also called Tahiti System). This can create confusion in those who buy a jewel with pearls.
The AAA rating system evaluates pearls with a scale ranging from A (lowest vote) to AAA (highest vote). Usually this classification is used for freshwater pearls and Akoya, but it can also be referred to for Australians and Tahiti.
AAA High quality, with no defects. The surface of the pearl has a very high shine, and at least 95% of the surface has no defects.
AA + High quality, luster, 85% of the surface without defect.
AA The surface has a high shine, 75% of the surface has no defects.
A + Luster not very high, surface with some defect, but below 25%.
A Luster shade, more than 25% of the surface with defects.
A-D classification (or Tahiti system)
Consider pearls on a ladder that goes from A (highest vote) to D (lowest vote). It is used in particular in French Polynesia.
A high shine and minimal imperfections, below 10% of the surface.
B High or medium shine, imperfections up to 30%.
C Medium shine, imperfections up to 60%.
D Imperfections on 60% of the surface.
The dimensions matter, in this case: the most sought-after pearls are the big ones. In very rare cases the diameter reaches 2 inches (australian ones). Usually, however, they are smaller: from a diameter of even less than 1 millimeter to an average size of 6.5 to 7 millimeters.