IV. Mabe Pearl Production Technology

Ever since those Chinese monks started their first cultured blister pearl, the technique has basically remained the same: an “implant” is glued to the inner shell of the mollusk, under the animal’s mantle. The mantle will cover the said implant and then slowly secrete nacre on top of it until -some months later- the Mabe blister has a good enough coating of nacre to be harvested and processed.

One of the important aspects of this pearl producing technique is the use of a wide variety of “Mabe pearl implants” (or “Mabe inserts” as they are also called). Most of these are made of plastic, but some are made of shell and other materials, and the use of plastic allows for the easy and cheap manufacture of these inserts (pricing is usually between 1 to 10 American cents per piece). Another added benefit of this material selection is that they can be produced in every conceivable shape (drops, stars, ovals, squares, hearts, animal shapes, even brand-name logos) and sizes (from 3 to 30 mm in diameter).

Mississippi mussel shell nuclei
Comparison between a 12 mm Mississippi mussel shell nucleus (left) used for loose pearl culture and a 15 mm hemispherical Mabe pearl implant (right).

Mollusks used for Mabe pearl production are usually the larger and older animals, with the less concave (flatter) shapes. The mollusks are left to open and then wedged to keep them that way. The pearl technician will use a “spatula” like tool to gently detach the mantle from the shell, then the shell is inspected for imperfections and cleanliness; if the shell has mucus it has to be removed (usually with a cotton swab) for the implant to adhere properly to the inner shell.

Implanting hemispherical nuclei to grow blister (mabe) pearls
Rainbow-lipped pearl oysters that have been pegged open and have their mantles pushed back and have been implanted for Mabe pearl production. Care must be taken in order to avoid the implants placed on the opposing shells from touching each other.

The implant is placed with the flat side up, and a small drop of glue (usually a cyanoacrylate or “Super Glue”) is added. Then, using a special hoop-looking tool (Mabe Inserter) or tweezers, the implant is picked up to be placed on the nacreous lining of the shell, avoiding any soft tissues, and then left to dry for at least 3-6 minutes. The animals are then taken back to their culture cages and to their farming site to begin the Mabe pearl culture period.

This video gives you a very good idea of the different methods used to grow Mabe pearls around the world:

Pearl oysters are placed inside protective cages or hung-directly from ropes. Ropes allow for the best water flow and for less maintenance, but in sites where predators are common, it will be necessary to use pearl farming cages.

Rope culturing (chaplets) and lantern nets to protect the pearl oysters
Culturing Mabe Pearl Oysters. Left: “Rope culture”. Right: Protective cages (“Lantern nets”) to avoid fish predators.
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