The pearl is the pre-eminent virgin gem, the only one produced by the sea and the only one to develop perfectly with no need to be either cut or cleaned. A natural product which generates spontaneously inside some molluscs which react to the presence of a foreign object, as for example a grain of sand which becomes isolated by layers of an iridescent substance until the development of a pearl. You try to activate the same biological process as the development of a natural pearl by implanting a foreign object to initiate the cultivation of a pearl.
Yielding molluscs are extremely delicate creatures and just a very small percentage of them produce pearls, just one or two out of a hundred are considered perfect.
Therefore a pearl, whether it is cultivated or is natural, is considered as a miracle of nature. The market value of a cultivated or natural pearl is based on various factors besides its size: Shape: a perfect sphere makes an exceptional and rare pearl, but also pearls with magnificent unique shapes are to be admired; e.g. drops, pears, bottoms and baroques or even twins. Colour: differs according to the kind of mollusc, their home waters and their nutrition. The colour can be observed under two different bases; the underlying colour and the tone colour.
Pearls have infinite combinations and variations of colour which makes it difficult to categorise them, but it is important to consider the colour's homogeneity and the harmony of the colour spectrums.
Surface Appearance: to estimate a pearls surface you consider outside signs such as scratches, cracks, convex or concave points in the pearl. Orient: this is the natural lighting of the pearl with reference to optical phenomena such as dispersion of light, reflections and refraction. It is a function of the size of the crystals of which it is composed and the thickness of the nacre. Nacre: is observable by x-ray analysis or if you have great experience, with a microscope looking towards the hole.