In reality, virtually all opals will craze or crack in
time....some will do it early, others take years.
I have opals I cut 20 years ago, I still have them, they are not
cracked and not crazed. Lalique made pieces with opal, I believe in
the late 1800's, I saw them at L.A. county museum. They were not
cracked, not crazed. I have about a pound of opal I have had for 20
years, uncut. Very few pieces have crazed. The most unstabile is
Mexican jelly opal or Virgin Valley, Idaho.
In my experience, most opals are cracked by the wearer smacking it
against something and shattering it. I believe that it is a myth
that opals dry out. I live in Denver, low humidity, very dry
dehydrating environment, and we have had very good success at
carrying opal at our retail store for over 10 years. A few doublets
have seperated, and a few have spontaniously combusted.(kidding)
Over time, some opals can craze, compared to how many I have, the
number that did craze would not be a deterant for me to not work
with them. I have paid $5,000 an ounce for some material,so I would
be very unhappy if my investment disintegrated over time. What I
have has gone up in value as some opal mining areas are not as
productive now as they once were.
I am not discrediting your experience, it just that my experience
seems to have been different. While cutting opals I have never
ruined the color by overheating, or cracked one during cutting or
polishing. I have gone through color layers, and lost value by
grinding away too much, and I have oriented opal wrong so the best
color was visible only at a significantly tilted angle.
Repolishing opal usually involves resanding as wearing causes
scratches and pitting. Polishing usually does not help unless the
scratches and pits are removed.
Richard in Denver