(These pearls are cultivated in Australia, Indonesia and the Philippines)
The oyster that produces these pearls is called Pinctada Maxima, and is cultivated in the sea. These are pearls whose nucleus has been grafted with a piece of epithelium from another mollusc of the same species.
The oyster can be grafted several times but it produces only one pearl at a time, after a gestation period of up to 3 years, providing larger nuclei in order to obtain larger pearls.
The colour and hue of the Australian pearl (pinkish-white or greyish) is natural and is due to the large amount of nacre that this oyster can secrete. Its coating is 2 millimetres thick and up to 6 millimetres thick, producing a fairly thick coating, which allows for a larger size and a unique appearance. Average sizes of Australian pearls range from 8.5 millimetres to 20 millimetres.
In order to analyse an Australian necklace we have to take into account different points such as:
The pearls are produced in nature by oysters, so it is rare to find perfectly round pearls, which is why the rounder a pearl is, the more valuable it is.
Cultured pearls are measured by their diameter in millimetres. The price increases progressively with the diameter, with significant differences for the larger sizes ranging from 8.5 millimetres to 20 millimetres in diameter.
The most common colours are:
white (there are different shades of white), pinkish white, silver, gold, pink and a cream colour.
4. Surface quality:
This refers to the absence of spots, bumps or indentations on the surface of the pearl. Although this is something that the oyster develops completely naturally, the more perfect the pearl, the higher the price.
5. Orient and luster:
The effect of light on the different layers of the pearl is the Orient. It is therefore essential that a good quality pearl has a high lustre and uniform intensity.
6. The thickness of the culture layer:
The thickness is of extraordinary importance. A coating of 2 millimetres is considered to be of very good quality.
It can be said, as recommended, that good fluorescence is indicative of a good pearlescent layer and greater durability.
Round pearls are the best known and most used. They are also perfect and the more mother-of-pearl they contain, the higher the price.
These are pearls with an irregular shape, they are used in jewellery making for their versatility. The price varies according to the quantity of mother-of-pearl and the size.