V. Processing Mabe or Natural Blisters

Since these pearls are not very useable in jewelry with the entire shell, they are processed: first they are cut from the shell, with the help of a handsaw, Dremel tool, core-drill or tile cutting saw. The type of tool will depend on availability and production volume, the first used mainly by occasional processing and the latter for commercial production.
Mabe pearl process.

A lineup of the Mabe pearl process.
Once the blister is separated from the shell, these are rinsed to remove grime, dead animals, and mucus. They are then left to dry in a shaded area, exposing them to the sun may have unwanted results like inducing cracks.

Once the piece of shell and pearl has dried out, the backside of the shell is removed by “popping” it out with a flat tool (such as a flat screwdriver). The inside of the dome is cleaned and the “Mabe insert” is also removed. Finally, the frontal piece is given a “shape” by drawing a shape around the blister to give it a final appearance.

The blister is then filled with a plastic resin. In times past the filling material could have been beeswax, tree-sap, metal shavings and lead. Depending on the variety of pearl, the filling may be colorless, white, or colored. Colored resin is mostly used on thinly coated Mabe pearls to give them “color”, as it will be seen through the nacre layer. The usual colors used are blue and pink, but many other colors can be used on demand.
Step by step, turning a blister pearl into a mabe pearl
Collage of Mabe Pearl Process at the Cortez Pearl Farm in Mexico. 1 & 2: Cutting Blisters from their shells using tile cutting equipment to increase production. 3: Cut blisters are washed in freshwater for a couple of hours. 4: Blister pearl after washing and drying in the shade. 5: Removing the back cover (shell) from the blister pearl. 6: Drawing a shape on the blister. 7: The inner dome is filled with an epoxy resin and left to dry. 8: Blister is ground around to the selected shape and also on the back to remove excess resin. 9: A piece of mother-of-pearl shell is affixed to the back side and the pieces is gently polished to remove debris and have the final piece ready.

Once the epoxy has dried, the piece can be sanded down to the chosen shape, and the back is smoothed as well to allow for fixing the backside of the finished Mabe pearl: a polished piece of mother-of-pearl shell.

The mother-of-pearl shell back can be made according to the needs of the Mabe pearl producer. It can be thin and flat, or thick and domed. The decision is made based on the producer or the jewelry setting planned for the piece.
Mabe nucleus and blister pearl still in shell
Two fully processed Mabe pearls from the “Mabe gai” pearl oyster. On the right side we have the “Classic Mabe” (perfect dome, round shaped) and a larger Mabe Blister (with some shell, oval shaped, concave shaped).

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