First, why do solder joints get pitted? I use an
acetylene/air torch, Prips flux, and I just used 14kw easy, 14ky
easy, and 10ky medium on four different rings and I saw pitting on
the sides of all four rings!
Make sure the seams are tightly fitted, and clean of dirt, etc.
Though prips flux is an semi-OK soldering flux, and essential on
silver to prevent fire scale, it really isn’t all that good a
soldering flux, especially for gold. You’ll get better solder flow
with fluxes more specifically intended for soldering (prips is a fire
scale preventor, but is relatively “low activity” for a soldering
flux) Try batterns, or similar.
Also, the easier grades of gold solders are easy grades because of
the inclusion of elements like zinc, and sometimes cadmium, to lower
the melting point. These componants are more easily volatilized if
you overheat the solder, which will give you pits. higher melting
grades of solder, though needing more care in use to avoid melting
the parts, give less pitting. Related to this, though it’s often
common practice to place solder by balling it up with a torch, picking
up the molten ball with a solder pick, and using that to place the
solder, this practice has it’s drawbacks. In many cases, you’ve
overheated the solder when you balled it up, and the solder not only
will now not flow quite as well, or as at low a temp, but it’s sure
to give you more pitting. With gold solders, especially easier
grades, you’re best off cutting paillons and placing them on the
seams, so the solder is first melted only when it then can flow into
the seam. Use no more than needed, as excess solder also can
contribute to pitting.
Pits form when dirt or oxides prevents solder flow leaving a pocket
that didn’t fill, or when componants of the solder vaporize, leaving
gas bubbles, or if molten metal is heated to the point, and long
enough, that either gas from the flame, or gas from the atmosphere,
dissolves in the molten metal but then comes out of solution when the
liquid solidifies, again leaving you with bubbles. The first two
reasons are the more common.
Very closely fitted joints, though not preventing the problems that
cause pitting, restrict the size of the gap in which gas bubbles
(pits) can form, thus the pits, if any, in a finely fitted seam, will
be much smaller and less noticable. Also, closely fitted seams
promote the capillary flow of the liquid solder into the seam, so the
seam fills more quickly and more easily, so you’re less likely to
overheat the solder. And the need for less solder to fill a tight
seam also contributes to less pitting, and a much stronger joint
too.
The jeweler refused the job due to not having the insurance to
protect himself if the emerald cracked.
While it’s common for jewelers insurance to have sufficiently high
deductables so the average consumer’s stone isn’t covered, most
jewelers who’re worried about this, simply ask the customer to assume
the risk, or a part thereof, if they’re not sure of the safety of the
job. But I’d rather have a jeweler who knows his limits, refuse
something he’s not sure of, than to take it and then cause damage due
to overextending his abilities.
Emeralds can be fragile, and a setter needs to take proper care, as
well as having enough experience with these stones to know how to
handle them with reasonable safety.
jeweler offered to redesign the earrings using the current
settings.
Huh? why would this be safer? Unless it’s only minor work, chances
are the stones would have to come out to do the work (unless the
jeweler has a laser welder, but even then considerable care is
needed, since lasers can still damage an emerald. While resetting a
stone in an existing setting is a little safer than setting in a new
setting, it’s still almost as risky as setting in a new setting…
Here's where I get lost...After putting the earrings in a copier
(?) the emeralds showed up yellow (?)(!) The jeweler declared the
emeralds fakes.
Try though I might, I can think of no gemological equipment that
looks like a copier, into which the stones might be put, other than
perhaps some sort of ultraviolet viewing cabinet. The main “fakes”
I can think of that might be detected that way would be some
synthetics that might show a little bit of red glow, not yellow. But
even that isn’t conclusive. “Fakes” is a strong term. I’d guess
they have to be glass to call em that, and glass is easily detected
with much smaller equipment, often just a loupe, or perhaps a
pollariscope, which doesn’t even closely resemble a copier.
Are you sure this guy was trained in gemology? Or perhaps your
grandmother is relating the tale with less than perfect accuracy.
I’d suggest having her take the stones to someone else, making sure
they’re credentialed gemologists (GG, CG, FGA, etc.) to get the real
story. And find a jeweler who’s got more experience in setting
colored stones, too, while you’re at it. A competent jeweler should
be able reset your grandmothers stones, even if only at her risk.
Your grandmother apparently found someone either without adaquate
experience in identifying gems, or perhaps without adaquate ability
to correctly explain their findings. Just saying “they’re fake”
isn’t really a complete explanation. It seems to me that the
likelyhood of the stones being just cheap glass fakes, if the
earrings themselves are otherwise good quality and also set with
diamonds, isn’t so certain, though it’s possible. More likely, if
they’re not fully natural stones, might be synthetics, which still
have value. And in any case, if these are a sentimental memento of
your grandfather, then there’s still no real reason why the stones,
even if just glass, couldn’t be properly reset into something your
grandmother will enjoy wearing.
Many (most) emeralds are treated with resins etc. to fill up
cracks. This is and has been for a long time a normal practice. So
it could be that the resin pours out while cleaning it in f.i. an
ultrasonic bath. That may change the color and clarity of the
stone a lot. Funny thing is that the jeweler knows that emerald is
very brittle, but apparently didn't check for resins.
While emeralds have been historically “oiled”, or filled with
resins, actually detecting these treatments is sometimes not a
trivial task. Sometimes it shows up, but other times testing for it
conclusively is not just a quick check. Many jewelers don’t actually
check for oiling or filling on most commercial grade customer’s
stones, since the vast majority of emeralds are treated. Instead, the
stones are simply assumed to have been so treated, and should always
be handled on the basis of that ssumption. The filling materials
are usually reasonably stable these days, and in most cases, don’t
“pour” out of a stone. Stones treated in recent years with actual
resins, usually aren’t so prone to having them be removed with a quick
normal cleaning in an ultrasonic. Some of the older, more highly
liquid, oils that have and sometimes still are, used, can be
compromised. One doesn’t have to remove much from surface fractures
for the stone to then look a good deal worse. Usually it’s just the
clarity that’s affected, unless the “oil” was actually dyed, which
is fortunately, not so common, and is considered unethical. In any
case, cleaning any emerald should be done with considerable care.
Even untreated emeralds can occasionally be damaged by the energy
levels in an ultrasonic, or the temperature shock of a steam cleaner.
Peter Rowe
