Restoring finish to opal

Richard,

Twenty years is nothing in the life of an opal. Even a hundred
years is nothing. All I said was that, in time, virtually all opals
will craze. Some won’t make it to the cutting stage, others wait
till they are cut before crazing. Some come off looking just great
and may stay that way for many many years. Well past our lifetimes
they may just decide to craze. I too have opals that have been in
my collection for well over 20 years both cut and uncut. Many have
survived but many have decided to give up the ghost. It sounds like
we share many opal experiences in our cutting careers. But I will
never let the potential problems with opal deter me from cutting
them either. They are still one of my favorites but then, I never
yet have met a stone I didn’t like.

Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry! @coralnut2

    On a slightly different topic: I have heard that it is
possible to "hide" crazing fractures in an opal. Does anyone know
about this? 

Oil and wax have been used to disguise crazing for quite a long
time. Plastics and epoxy resins such as Opticon are being used often
now. Since two-part epoxies also harden, they are considered a good
stabilizer for opal, turquoise and other porous stones. Whichever
the desired result, be it stabilization or to hide crazing,
non-disclosure is considered unethical.

I recently went up to Mississippi to visit, and ran across a friend
with a simple Lightning Ridge opal pendant I made years ago. The
little black stone had developed a crack (as in ‘deeper than a
craze’) from one edge up over the top a little. I offered to update
the setting for her, and mentioned that while I had the opal
removed, I could treat it with a resin, which could help restore
some durability to her opal. She agreed, and I must say I was as
happy as she after seeing it’s appearance. Most of the crack was
invisible from the top over the side, and the rest was under the
bezel.

I believe this was a happy experience due in major part to
disclosure of the treatment. I explained that we weren’t trying to
hide the crack, rather trying to stabilize it before it went any
further. Treatments have their purpose, but “hiding” inclusions and
imperfections is not an ethical one. Besides, I’ve seen many crazed
opals that were far more interesting because of this “defect.”

James in SoFl

P.S. Oh, and don’t forget about water for hiding crazing in rough.
Seldom do I see rough opal for sale outside of a water-filled bottle
of some sort.

    On a slightly different topic: I have heard that it is
possible to "hide" crazing fractures in an opal. Does anyone know
about this? 

I’ve heard it too, yet among the opal repairs that I have done in
the past, have come to believe that there is nothing to be done with
crazing. I also wonder if there is something other that cracking
that is happening.

Bruce

   P.S. Oh, and don't forget about water for hiding crazing in
rough. Seldom do I see rough opal for sale outside of a
water-filled bottle of some sort. 

James,

When cutters buy rough, like lapis, turquoise,opal…agate ect,
they wet the rocks to see what they will look like polished. What a
rock looks like wet is usually what it looks like polished.

Bottles of opal are usually parcels of material that will cut
similar stones in color, pattern of fire, andprice. Every opal
dealer I have delt with for 20 years has allowed me to open the
bottle to inspect each and every piece. Water makes the stones look
bigger and better, but it is used as a tool for inspection, not
deception. I personally have never seen a dealer putting crazed
australian opals in a water filled bottle. If someone did that,
they would lose credibility immediately from any cutters that knew
what they were doing.

I have seen bottles of mexican jelly opal in matrix for sale that
had some stones in the lot that had crazed or cracked, and that is
the way that material is sold. If you are lucky with that material,
you get a few nice stones and some specimens for kids. Blasting is
used to remove material to get at the mexican jelly opal, and that
causes cracking which is usually easy to see.

There is a learning curve to buying good rough. Everyone that buys
any kind of rough knows this. Part of the thrill and adventure.