Keshi pearls can grow in any pearl-bearing oyster, which lives in sea water, or any pearl-bearing mussel, which lives in fresh water. Thes are all nacre pearls, with no nucleus, which are frequently formed when the 'seeding' fails. They are often on the small side, from 2mm upwards, however, some South Seas examples can reach much larger sizes, around 5-8mm. Seawater Keshi pearls (Akoya, South Seas and Tahitian) are now extremely rare, as most producers now x-ray the oyster, to see if the nucleation was successful. Keshi pearls can be any shape or any colour, depending on the host mollusc. Sometimes the re-seeded mollusc can grow a keshi pearl in a used pearl sac and these are often referred to as second-harvest keshi pearls. This term can also be used to describe keshi pearls which have been returned to a mollusc to grow larger. Although keshi pearls are naturally formed by the mollusc 'doing it's own thing', nowadays, all keshis produced are regarded as 'cultured' (farmed by man) pearls. Occasionally, a strand of natural keshis turns up, which is vintage and extremely rare.
Original Lake Biwa pearls are an unusual find these days, because Japan's freshwater pearl industry is very depleted. Pearl production all but stopped there in the 1980s, due to the pollution etc. of the growing area, Lake Biwa-ko. Occasionally a rare unused strand emerges, having been hoarded and never used, but the majority of finds today are in vintage jewellery. Luckily the Biwa mollusc was crossed with a Chinese mussel and some beautiful and very lustrous new Biwa pearls, the result of this union, are being produced today. Do not be fooled by the use of the term 'biwa', which became a generic term for all freshwater water pearls from the 1930s to the 1980s and is still used today to describe long freshwater pearls. These have no connection with the original Lake Biwa or the new Biwa hybrids, but are simply long freshwater pearls from a different Chinese mussel.
One of the most unusual and rare pearls is a natural pearl, (found, not farmed). These pearls are formed naturally, when an irritant, such as a grain of sand, enters the mollusc and is then coated in nacre to stop it from irritating its host. The Abalone (Paua) produces such pearls, which are baroque and have the colours seen in Paua mother-of-pearl, often used for jewellery. These are the stunning tones of turquoise, green, purple and blue, so the resulting pearl is just amazing and quite rare. These can never be farmed, as the Abalone is a haemophiliac and cannot be seeded. Other natural pearls include the Conch (pink) and the Giant Clam (opaque white) to name but two.
forthgirl at Culross Creations.......shop http://stores.ebay.co.uk/Culross-Creations?_trksid=p2047675.l2563
My Akoya pearl guide can be found at:- http://reviews.ebay.co.uk/About-Akoya-pearls?ugid=10000000176473258
My freshwater pearl guide can be found at :- http://reviews.ebay.co.uk/Pearls-Freshwater?ugid=10000000176617237
My South Sea and Tahitian Pearls guide can be found at :- http://reviews.ebay.co.uk/Pearls-Unusual-and-Keshi?ugid=10000000176617141
My Nucleated and Flameball pearls guide can be found at :- http://reviews.ebay.co.uk/Flameball-and-Nucleated-Pearls?ugid=10000000176616995