These are the classic freshwater pearls, in production since Hieriopsys cumingii sān jiǎo bèi 三角貝 mussels came into use in China during the 1980's. Pearls of the first harvest tend to have plump or full shapes. Few are spherical, but the typical ovoid/drop and cushion/lentil shapes attest to the abundance of nacre that a mussel in its rapid growth stage produces. Relative roundness is easily compared, and costly to specify in freshwater pearl orders. It also seems to vary inversely to strong lustre, more frequently found in ovoid pearls. Probably the most intensive lustre-enhancing treatments are lavished upon the roundest pearls, because their scarcity enables them to fetch higher prices. To 2010, China produced far rounder pearls without nuclei than with round bead nuclei. For pictures and more detail please see flame type bead nucleated pearls and in-body bead-nucleated pearls . Read on for more details on non-nucleated fw pearl farming.
Non-nucleated (regular) Chinese freshwater pearls - details
The easiest type of freshwater pearls to be farmed, regular non-nucleated fw pearls are produced by grafting pieces of active mantle tissue into the mantle of another mussel. Mantle is a mollusc's skin, an organ that grows its protective shell apace with the rest of its body. The most active area is a band close to the open edge of each wing of the hinged shell. Small pieces of living active mantle tissue are inserted into various areas of the envelope. Unless the graft is premature, the nacre it produces does not become part of the shell. Instead, it is a foreign body that the graft grows to surround, thereby becoming a pearl sac. All pearl cultivation depends upon successful creation of a pearl sac. Because mussels can live for many years, quite large non-nucleated pearls can be produced. It is said that, with just the right placement, surprisingly round pearls reaching unusual sizes can be achieved. This occurs infrequently, because it depends upon both ideal graft placement and the pearl's remaining in the mussel much longer than usual. However, a cultivation effort as big as China's can be expected to include quite a few such universally desired exceptions to the rule that roundness varies inversely to size. In classical non-nucleated freshwater pearl cultivation, the first harvest will occur 2-4 years after the first operation, because the majority of pearls will not benefit from more growth. This is because many run out of space in the mantle, and if they continue to grow their shape will become severely flattened. If the mussel is kept alive after the first harvest, the pearl sacs will produce again. As the mussel reaches adult size, growth slows and the production of nacre diminishes. Hence non-nucleated pearls from the second and subsequent harvests (also known as China freshwater keshi) are usually thin, with concavities and character mostly absent from the first harvest. Their look differs so much that it is hard to imagine they come from the same animals. Please see our page describing second harvest pearls aka Cfw keshi, accessed from the homepage or sitemap. Non-nucleated means cultivated without the use of a nucleus (such as a shell bead or flat button). A phrase used commonly in English to express this is "tissue-nucleated", an oxymoron implying the tissue is inside the pearl! The grafting of active mantle tissue is necessary, whether or not nuclei are used, in order to form the pearl sac, without which no pearls can be grown. (Mobe grow as part of a shell, and do not require mantle tissue grafts - but are outside a strict definition of pearls). Because ocean pearl cultivation requires in-body nucleation, even the earliest Japanese efforts with freshwater mussels used this method. Cultivators made a few non-nucleated pearls in the mantle as an afterthought. Only after it was discovered that people in traditional natural pearl markets would pay more for non-nucleated pearls the Japanese call keshi were these cultivated in quantity. Chinese cultivation efforts on the other hand began with no-nuc mantle cultivation, at least partly because it is far less demanding of surgical skill and hygiene than in-body nucleation. This method probably still accounts for the lion's share of Chinese pearls as of early 2011.