I found out that they are called bamboo coral, whose color is irradiated red, which means it is subject to fading and/or bleeding.
Well, I could be wrong here. But if he/she says a radiation
treatment results in a color that can bleed, I’d be VERY suspicious.
radiation changes the color of existing components of a material. If
it bleeds now, then it could have bled out in whatever color it was
prior to irradiation. And that’s not normal behavior for any gem I’m
aware of. Again, I’d suggest to you that this is, in fact, a dye.
maybe dye plus irradiation…
the only other thought I have which might support that
irradiaton/bleeding claim is that if the irradiation is producing
significant damage to the material (usually by heating), it might
produce a dusty residue from breakdown of the material. That might
rub off leaving a stain of sorts. if that’s the case, then i’d think
a good cleaning in the ultrasonic should solve the problem. But
frankly, I rather doubt this is the answer. I don’t think
irradiation treatments are normally carried out at levels which
cause significant damage to a material… Certainly, I’ve never
seen any sort of "bleeding’ problems from the colors found in various
irradiated cultured pearls that are widespread on the market, and in
fact, even color bleeding from those that are also dyed isn’t common,
at least I’ve not seen it before. Treating coral shouldn’t be too
different from pearl, since they’re somewhat similar chemically.
About opticon: This is a two part epoxy resin. Normally one soaks
the stones in just one of the resins, letting it penetrate. Then one
coats the surfaces with a mix of the resin and a hardener, so that
this surface layer seals the still liquid resin inside and the
surface is then stable. You could do just the latter part, since you
don’t really need the resin to penetrate, I’d guess. The trouble with
opticon is that it’s a sticky mess to work with. You need to soak
the stones and then be able to wipe them clean. This will be hard
to do with your already strung necklace. At the least, you’ll have
to take the thing completely apart to use opticon. And cleaning the
surface traces of visible resin off the coral branches may be
difficult if they’re complex nobby shapes.
if it were me, I think I’d return the corals for a refund.
Peter Rowe