Animal husbandry – Aquatic animal culturing – Mollusk culturing
Reexamination Certificate
2000-07-10
2002-01-29
Jordan, Charles T. (Department: 3644)
Animal husbandry
Aquatic animal culturing
Mollusk culturing
Reexamination Certificate
active
06341580
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the culturing of half or mabe pearls in molluscs. In particular this invention relate s to a nucleus suitable for enhancing the growth of half or mabe pearls in molluscs, and a method for the production of cultured half or mabe pearls.
BACKGROUND
The active production of half or mabe pearls in mollusc s by way of inserting a nucleus, or foreign body, into the tissue of the mollusc, to stimulate the production of calcium carbonate, or nacre, is well known. The nucleus may be implanted into the gonadal tissue of the mollusc, or attached to the shell in such a manner that it directly contacts the mantle tissue of the mollusc. Pearls produced by the artificial introduction of a nucleus are known as “cultured pearls”, and “maybe” pearls are produced when the nucleus is attached directly to the shell.
It is also known to vary both the composition and shape of the nucleus in order to obtain some degree of control over the final pearl product. Variations in the composition of the nucleus can result in some control over various factors, such as the colour, texture and hardness of the pearl. Varying the shape of the nucleus can, for example, affect the shape of the resultant pearl, and the time it takes to form.
A large number of techniques have been developed to insert the nucleus into the host mollusc, to try to improve, such factors as the ease of insertion, the mortality of the molluscs and the percentage recovery of pearls.
The time taken from the implantation of the nucleus to the harvesting of a fully developed pearl can be from eighteen months to two or three years, depending on the mollusc and the external conditions. The longer the time, the higher the cost of the pearl production. Furthermore, the risk that the mollusc will not live long enough to complete the process of forming the pearl increases. It is therefore very desirable to reduce the length of time taken from the implantation of the nucleus to the formation of the complete pearl.
In the production of half or mabe pearls in particular, there can also be a problem with achieving an even deposition of nacre over the entire nucleus. The nucleus traditionally used is in the shape of a hemisphere, and there is a problem in that while a substantial thickness of nacre is usually deposited at the base of the nucleus, very often only a thin layer is deposited at the top of the hemisphere. Once the pearl has formed it must be removed from the nucleus, and the hemispherical pearl shell so obtained is then filed with a resin before being mounted into the desired item of jewellery. If the top portion of the half or mabe pearl formed is thin it is prone to breaking, either on removal from the nucleus, or in subsequent use.
There is a need for a method of producing cultured half or mabe pearls which can increase the percentage success of pearl formation within molluscs to which nuclei are inserted, decrease the time taken for a layer of nacre to deposit on the nuclei, and assist in the deposition of a uniformly thick layer of nacre over the whole of the nucleus.
OBJECT
It is an object of the present invention to provide an improved nucleus for the production of half or mabe pearls in molluscs, or to at least provide the public with a useful choice.
STATEMENT OF INVENTION
In a first aspect this invention provides a nucleus for the production of half or mabe pearls in molluscs comprising a first portion having an external surface adapted to define the shape of the half or mabe pearl to be produced and a second portion which defines a bridge between said first portion and the shell of the host mollusc whereby to enhance the development of said half or mabe pearl during production thereof.
Preferably the second portion comprises at least one part of, or all of the primeter of a base of the first portion, and extends outwardly and downwardly from the first portion.
Preferably the said second portion extends continuously around the whole perimeter of the base of the said first portion.
Preferably the said second portion is formed as a concave curved surface extending outwardly and downwardly from the said first portion.
Optionally the said second portion is fringed or perforated in some way.
Preferably both the first and second portions of the nucleus are formed integrally. By integrally is meant that the first and second portions are produced as one single unit or piece.
Preferably the first portion is substantially hemispherical.
In another aspect the invention provides a method of culturing half or mabe pearls in molluscs comprising:
(a) introducing a nucleus comprising a first portion having an external surface adapted to define the shape of the half or mabe pearl to be produced and a second portion which defines a bridge between said first portion and the shell of the host mollusc whereby to enhance the development of said half or mabe pearl during production thereof, into the shell of a host mollusc;
(b) culturing said host mollusc; and
(c) harvesting a pearl from said host mollusc.
Preferably the host mollusc is an abalone or paua. Optionally the mollusc is an oyster, mussel, Cook's turbin or cat's eye. However it is envisaged that any mollusc in which a pearl may be cultured is within the scope of this invention.
In yet another aspect the invention provides a half or mabe pearl which has been cultured in a mollusc by inserting into the said mollusc a nucleus comprising a first portion having an external surface adapted to define the shape of the half or mabe pearl to be produced and a second portion which defines a bridge between said first portion and the shell of the host mollusc whereby to enhance the development of said half or mabe pearl during production thereof
Preferably the half or mabe pearl so formed is substantially hemispherical in shape. In a most preferred embodiment the half or mabe pearl is either a half ball or a three quarters half ball.
Option ally the half or mabe pearl can take any desired or required shape. Some possible shapes are tear drop, heart, star or oval, but any other shape which may be formed from the nuclei of the invention are envisaged as within the scope of the invention.
In an optional form the nucleus may be formed from a malleable material and with the base of it being slightly concave. The nucleus may then be fixed in place on the shell of the mollusc by applying pressure from above so that it can be squeezed and flattened to allow for vacuum attachment to the shell.
While it is preferred that the first portion is formed in the shape of an hemisphere, it is envisaged as within the scope of the invention that the said first portion may take any other shape in which it is desired to form the half or mabe pearl. If the half or mabe pearl is to be hemispherical it may formed as either a half (a full hemisphere), or three-quarters of a half ball (a full hemisphere with the bottom one quarter removed).
While it is preferred that the first and second portions of the nucleus are formed integrally, that is, in one piece, it is envisaged as within the scope of the invention that the nucleus may be provided in two or more parts which may be subsequently connected, either prior to insertion in the mollusc, or as part of the process of insertion. In particular the said second portion may be formed as a separate skirt or base portion into which the said first portion may be fitted.
It has been found that the nucleus can be adapted most particularly for successful insertion into the mollusc if the said second portion is formed of a reducing cross sectional thickness as it extends outwardly and downwardly from said first portion. The thinner the said second portion is, the better it is able to mold to the variable contours of the shell, and so assist in a more secure positioning of the nucleus.
While the nucleus may be merely pressed on to the shell of the host mollusc it is preferably introduced into the mollusc by any one of three methods. In a first method the nucleus is fitted with a tail, which extends from the central region of the interior
Greer Burns & Crain Ltd.
Jordan Charles T.
Langdon Richard W. N.
Smith Kimberly S
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