Welcome to the Coleman Douglas Pearls web site


Extract from a speech delivered by Christianne Douglas to the Gemmological Association of London, on the 22^nd April 1998.

EACH PEARL WHETHER CULTURED OR NATURAL IS TRULY INDIVIDUAL. The shape of a pearl will be largely due to the irritant that caused the pearl formation in the first place. This shape may subsequently be altered by: v An organic substance that attaches itself onto the growing pearl. When this substance decomposes the gases released create internal blisters in the nacre layers. This effect produces protuberances in the pearl. v A small pearl attaches itself to a larger pearl. The pearl sac surrounds both and continues to secrete layers of nacre. v The change in water temperature and salinity can affect the pearl sac, which may tear and form marks on the pearl. v A pearl while growing slides and is impeded by a muscle or organ in the mollusc to grow regular layers of nacre due to the restricted space of its new surroundings. v Pearls move and rotate while growing. A pointed object might constantly obstruct the pearl and this would produce a ringed or circled pearl, as the movement would have the same effect as that of moulding it on a potter’s wheel.

	Shapes in natural pearls can vary owing to the irritant, which caused the formation of the natural pearl in the first place. When natural pearls are found in strands they tend to be less closely matched in shape and colour tone due to their scarcity. Most shapes can be found in the classification for cultured pearls.



	Shapes in cultured oyster pearls. Unless we refer to the half-sphere found in the centre of a Mabe pearl, cultured oyster pearls have a large round portion in their bodies, where the mother of pearl spherical nucleus is located within the pearl. This bead is the same irritant that is placed by the technician into the pearl bearing oyster to start the cultured pearl formation. These pearls are termed nucleated.
	Shapes found in oyster cultured pearls –









	Shapes in cultured freshwater pearls can vary from very flat and dispersed to round because of their cultivation process, which involves placing a tiny piece of mantle containing epithelial cells from a donor mussel into the host mussel. The mantle can be cut into a variety of shapes. Once the tissue has triggered the pearl formation it dries up, decomposes and disappears, leaving a small hollow within the pearl. These pearls are termed non-nucleated.
	The flexibility this cultivation process gives to the eventual formation of the pearl allows us to find literally any shape. The most common are: