Types of Pearls
1. cultured pearls:
Freshwater cultured pearls offer an enormous variety of
shapes and sizes, which is why they are popular all over the world. The
size of the freshwater cultured pearls varies from 2 - 8mm, the average
measures approximately 4 - 5mm. Rarely freshwater cultured pearls with
a size of more than 10mm are found. Cultivation of those charming pearls
dates back until the 13th century. The famous Japanese 'Biwa' pearls used
to control the industry from 1924 until well into the 70's. The Biwa Lake
in Japan, like so many others, became a victim of environmental pollution
caused by adjoining factories and urban sprawl. The extensive freshwater
pearl production in the waters of Lake Biwa came to an end.
2. Akoya pearls
Since oysters are relatively small, the average size of Akoya pearls (Saltwater Pearls) varies from 2 to 9 mm. Originally cultured in Japan, the so-called Akoya pearls were the most popular saltwater pearls for almost a century. Until the 90’s the production was controlled by Japanese companies. As from 1990, China started cultivating Akoya pearls in remarkable quantities which meant serious competition for Japan’s production fairly soon. Pinctada fucata martensii, is the nomenclature for the double-shelled mussel of the species Pteriidae, used to cultivate Akoya pearls. Just like freshwater pearl production, the saltwater pearl cultivation starts by implanting a perfectly rounded mother-of-pearl nucleus along with an irritant into the oyster. Only two, maximum four nucleuses can be hosted at the same time, while freshwater pearl cultivation allows implantation of several more. Tahitian pearl cultivation allows one nucleus per mussel only. After the harvest, Akoya pearl producing mussels will not be nucleated again. Untreated Akoya pearls are mainly cream coloured, yellow or green. The pearls displayed in shop-windows are the result of a sophisticated treatment applied to eliminate impurities. Shapes vary from ovate, button-shaped, drop-shaped to baroque. The Value of Akoya pearls depends on their size, shape, colour and luster, as well as on the composition of their surface. For necklace of exceptional quality made of pearls measuring 8-9 mm, one has to part with a couple of thousand dollars.
3. Tahitian pearls:
The major feature of black Tahitian pearls is their large
size. Black Tahitian pearls belong to the group of South Sea pearls and
can measure between 9 and 17 mm. A thick and healthy mother-of-pearl layer
around the implanted nucleus creates an immaculately natural colour, luster
and beauty. These black pearls do not require any artificial improvement,
which is why they are admired as the "Queen of pearls".