Opal crazing (small cracks) can be one or two small cracks or a
heavy webbing or cracks. Opals have a certain amount of water
molecules in their structure. If dehydration of these water
molecules occurs, an opal is susceptible to crazing at any point
after that. The stone can have already been dehydrated when
purchased and you will have no knowledge of it. Dehydration can
occur from setting an opal out where it will get sun and be
warmed (and in some jeweler’s lighted showcases or their
windows). Amount of dehydration and potential seriousness of
crazing is dependent upon how much water is present in the stone
and how much vacates the stone. A stone with smaller amounts of
water will be more “stable” but could still craze. Crazing
usually occurs in the opal (after dehydration) when there is a
sudden temperature change to the stone (thermal shock). This
can be having the stone in a cold place and putting in a warm
hand, having the stone warm (being inside) and going outside
where it is very cold. Knew a lady a few years ago that would
put her jewelry in ice cube trays when she went on vacation (and
freeze her jewelry). She destroyed an new opal piece by doing
this. Al Gilbertson
Another crazed opal story: A neighbor of ours bought his wife a
gorgeous tenth anniversary present: a ring containing a HUGE
opal surrounded by diamonds. Very impressive piece of jewelry.
The first weekend after she got it, she wore it to a party, and
over coffee, the group got into a heated political discussion.To
emphasize a point, our heroine banged the palm of her hand on the
table, and the opal disintegrated! (marriage pretty nearly did,
too. She thought he had given her a
fake)…D.