I did the retipping with the created ruby in place as the Rio
personnel directed. "It will not damage the stone to apply heat."
Now that the ring is beautifully finished, I notice an
imperfection that is hard to describe but I am sure it is from
heating the stone. It looks like some kind of watermark or filmy
splotch on the surface of the stone. I cannot remove it with Zam,
cleaners, etc.
Well, for my money, I’d say it would be worth asking the idiots at
Rio to get you another stone for free, since you followed incomplete
advice. They are correct in the statement that ruby can withstand
the heating required to retip a prong, if you’re gentle about it.
Apparently, they neglected to mention the important bits that you
MUST be sure there is no soldering flux on the ruby, and you need to
be sure that you don’t let a highly reducing (gentle) flame play on
the ruby.
Ruby is aluminum oxide.
Soldering fluxes dissolve metal oxides
Reducing conditions such as very reducing soft flames, played on
metal oxides, can reduce them back to metals, at elevated
temperatures.
the upshot of this is that in all likely hood, you had flux on the
stone, and at soldering temperatures, it’s etched into the stone.
The flame, too, can cause damage, though usually the effect of that
looks like an oil slick of iridescent surface color, and you can
sometimes polish that off more easily, as it’s a surface film, not
etched much into the surface. The stone’s polish won’t then be as
good, however.
If you need to polish corundum (ruby, sapphire), things like
cleaners, rouge, and zam won’t do it. You can try the specialized
platinum rouge that Gesswein sells. it’s a highly graded aluminum
oxide itself, and will slowly put a little shine on most hard stones,
including sapphire and ruby. Note that this stuff is quite
different (and IMHO, far superior) to other platinum rouge products
sold by others. At least in the case of the flame damage, it can
be enough, though I doubt it will work for flux etching. More
effective is a lapidary diamond polishing paste. A 14,000 grit paste
should work well enough, but for a facetted stone, the trouble is
that for you, at the bench, to polish out the etching will leave you
with a lousy facet when your done. The better part of valor here
is either to replace the stone if it’s cheap, or to have a lapidary
repolish it. In all probability, this will require unsetting the
stone, unless the damage is only on the table, and the prong tips are
lower than the table. Repolishing the table is likely to run you
somewhere in the ten to twenty dollar range, I’d guess, unless some
kind Orchid reader who does facet cutting jumps to your aid…
Hope that helps.
Peter