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Mabe' mystery


#1

Hello eveyone,

I made a ring with a mabe’ oval and set in 14k yellow. The
customer brings the ring back and the pearl is in a terrible
state. A layer that looks as thin as an onion skin “popped” off
the dome of the mabe’. My question is this; is a mabe’ a
construct of plastic with a thin layer of pearl nacre that is
grown over it in the shell? Or, is a mabe’ a construct of
plastic that has an applique of pearl nacre attached to the
plastic formation? I have my receipt and invoice from the
wholesaler that I bought the pearl from. I am going to take the
pearl and the ring that still has the plastic form in it back so
they can see the damage and possibly determine whether or not
the pearl wholesaler needs to replace the item or if the
customer was uncommonly abusive to the pearl. Has anyone else
had trouble with the delicacy of these types of pearls??? I have
only worked previously with solid blister pearls and I think I
prefer them. The customer needed the price affordability of the
mabe’, but I am starting to suspect the yet again, you get what
you pay for…

Denise Jenkins
broken pearl and broken hearted in Santa Fe, Tx.


#2

Denise:

You’ve answered your own question. A pearl, reguardless of type
is always easily damaged. No help for it other than replacement.
Steve Klepinger


#3

It is my understanding that mabe pearls are created by attaching
a shaped shell core to the inside of a mollusk shell. The
mollusk then proceeds to cover it with layers of nacre. After a
specific amount of time the mollusk is harvested and the
resulting blister is cut away from the shell. Finally, a mother
of pearl back is added. It sounds to me like your customer may
have knocked the pearl against something hard enough to break
the thin layers of nacre and expose the shell core. I use a lot
of mabe pearls and occasionally have a customer who has cracked
or broken a pearl set in a ring. I generally replace it and
charge them for the new pearl. An expensive South Sea pearl can
be damaged by rough handling just as easily.

– Steven Brixner -
Jewelry Designer - San Diego CA USA
@Steven_Brixner3
http://home.att.net/~brixner


#4

Mabe’ pearls are almost always glued constructions. The blister
is grown normally in the oyster, over a half dome of either
plastic or cut from mother of pearl. I’ve seen both. After it’s
cut from the parent shell though, is sometimes needs to be
reassembled. Sometimes not. The back half is always an
addition, and you can always see the seam between front and
back. In a few cases I’ve seen these where the hollow nacre dome
has a bead, not a hemisphere, filling most of the bulk, with the
substantial remaining volume just filled with plastic or epoxy or
maybe even duco cement. Wasn’t sure what it was. Made a mess
when it came apart. You’ll find many of the solid blister
pearls are also similar, with a plastic dome under the nacre
surface, except that in those, it’s the original dome the pearl
was grown on with no subsequent addition of a seperate back.

The difference in quality between good and not so good mabe’s
does not depend on this filled construction, since they can all
be considered to be such constructions. Instead, like all
pearls, the real quality factor is the thickness of the nacre
layer (Plus, of course, flaws, color, orient, etc.) Good ones
will have the nacre blister a good 3/4 of a millimeter or more,
and these will hold up fairly well. Some, though, are almost
paper thin. It can be a real problem determining the good from
the bad, since the construction hides the edge of the nacre which
would allow you to see the thickness.

One unpredictable problem with mabes that have not had the
filling reassembled after being cut from the shell (most of them)
is that you then don’t always know how well the layer is
attached. Occasionally, one will just pop off as you describe.
But in my experience, as often as not, it’s the fault of the way
the pearl has been treated. Too much pressure while setting a
bezel, for example. Or the use of a harsh blast of steam directly
under the nozzle. Or solvents of some sort, such as in cleaning
off excess epoxy after gluing. That sort of thing, if it seeps
between the nacre blister and the filling, can easily seperate
the pearl. It’s happened to many of us now and then. if the
seperation did not damage the surface of the filling (many of
them are coated with a sort of reflective layer, which does
show through the pearl layer, increasing whiteness) you can often
just epoxy the pearl blister back onto the filling without too
much change in appearance. Be very careful to get an even,
bubble free layer of epoxy as thin as possible. A little tricky
to do, but sometimes works. If that irridescent coating on the
filler has been damaged, that area will often appear as a shadow
in the mabe after it’s reglued together, but even then, sometimes
its acceptable as a repair if you cannot replace the pearl for
some reason. And of course, if the nacre has been actually
cracked/damaged or punched through, the pearl is likely dead.
Whether you can request replacement of the pearl from your dealer
depends on the pearl and the dealer. If it was really costly and
represented as highest quality, and that nacre bubble is only .2
mm thick, you’ve got a valid gripe. If this came apart after the
customer spent all day with her hands in paint solvent while
repainting the garage, then I’d have to say the pearl only did
what it was gonna do with that treatment.

Hope this helps.

Peter Rowe


#5

Hello Denise,

Cultured blister-type pearls, also known as Mabe pearls are
formed when you insert a bead nuclei ( usually soapstone )
between the mantle tissue and the shell of an oyster called
’Pinctada maxima’. The mollusc is then returned to sea for a
period of 2 to 3 years, during which time the bead nuclei gets
covered with layers of nacre, which are attached to the inner
shell of the mollusc. It produces a blister-type pearl which is
attached to the shell. The blister-type pearl is then cut-off
from its shell and the soapstone bead is removed. The cavity is
then filled with wax or resin or sometimes a mother of pearl bead
is cemented. The back of the Mabe pearl is then covered with a
piece of polished mother of pearl.

The difference between a Mabe pearl and a cultured blister pearl
is that the latest is produced in the same way, except that
instead of a nuclei being used, a mother of pearl nucleus is then
inserted between the mantle tissue and the shell. Secondly, after
the pearl has been sawn from the shell, the mother of pearl
nucleus is left within the pearl. The base of the cultured
blister pearl will then reveal both the mother of pearl nucleus
and the nacreous skin.

The nacreous layers grow by 0.1mm to 1.5mm per year in ideal
conditions. Usually the thin layer of nacre of the Mabe pearls or
cultured blister pearls are generally between 0.5mm to 1.mm in
thickness.

Because of the way those pearls are constructed, and their
relatively thin layer of nacre, the Mabe pearls and the cultured
blister pearls are extremely fragile, knocks will often chip or
break them.

Best regards,

Francoise.


#6

A mabe is a cultured blister type pearl, made from the
clam/oyster/whatever at the end of its “useful” life. Then, back
at the factory, the mabe is cut out of the shell and assembled
with a backing, usually mother of pearl, and an inside round
bead, usually mop or something, not plastic.

You can expoxy it back together. A Mabe in a ring needs to be
worn gently.

-Elaine
Chicago, IL, US
Midwest