It has a large crack in the mounting visible to the naked eye. Do
you have any advice as to how this could happen?
A couple possibilities.
One might be a bad casting, if the ring was cast. Platinum can
present some difficulties if not cast correctly, including sometimes
rather dramatically sized shrinkage cavities which can weaken those
portions where they form. And cast platinum can have a very coarse
crystal structure (large crystals). In some cases, especially with
contamination of the platinum, the crystal boundaries can crack under
Another possibility is if the ring was built with a laser welder,
and not used correctly, or with an incompatible platinum alloy. While
most platinum laser welds very well, you can sometimes still get
cracks in the welds if you are welding flawed metal, or over a poor
solder seam, etc. Unlikely, but possible.
Another likely situation is simply that the ring was made with
platinum that had become contaminated. There are a number of things
that can be accidentally introduced to the platinum that can make it
brittle, either over the whole mass of metal, or in localized areas.
Platinum has a number of “rules” to follow when working it, which if
not paid attention to, can get a platinum smith (usually a novice
one) into trouble.
It may also be simply that in the making, that section of metal was
worked too much. Platinum can take a lot of working, more than most
other jewelry metals, but it too has it’s limits. If bent too often,
or stretched and stressed too much, it can form cracks. I’ll bet the
crack in your customer’s ring was already at least started there when
it left the shop, and has just grown bigger under the stress of use.
I would also bet that in most cases, a crack like that can be
properly repaired by any decent platinum smith unless the whole ring
is seriously flawed. Laser welders make that kind of repair pretty
easy, but even without, it’s possible in most cases. Sometimes stones
have to be removed first, but again, that’s easier to do with
platinum than with, say, white golds.