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Opal Setting?


#1

Anyone,

Yes, here I am again bothering everybody with another annoying opal
question. This question is more serious.

I have been struggling to learn some about the opal trade, because I
love opal above all other gemstones simply for the potential of
color, brightness, and general elegance.

I have been recently told that the best quality opal gems are never
set in jewelry for fear of stress fractures and damage from wear.
This is igoring the other potential problems like drying and
crazing. Anyone care to comment? I feel stupid because I set a
rather expensive stone in a 14k bezel some time ago to wear on very
special occasions under very safe conditions. I keep the stone in a
plain small cardboard box lined with thick cotton all around.

I very carefully examined the stone after setting and found no
cracks or crazing even under 16x, but still is the setting stupid
for valuable opals?

Thanks for your help.

Blaine


#2
I have been recently told that the best quality opal gems are never
set in jewelry for fear of stress fractures and damage from wear.

I have a collection of some 50 beautiful Opals from around the
world, all mounted in gorgeous hand-fabricated 14k rings and
pendants. These are VERY expensive stones that were collected and
set by one individual, and range from 1912 to 1945. Almost all are
bezel set. They have absolutely no crazing or problems of any sort,
and have surely passed the test of time.

Please don’t feel stupid. The bezel setting is the safest, and I
think they should be set and worn. A fine stone languishing in a
safe is enjoyed and appreciated by no one. Use common sense - no
gardening or auto mechanics while wearing it.

Jim Marotti Lancaster, TN


#3

We have set opals in value from $100 to $10,000 in jewelry. I have
never heard anyone say that you shouldn’t set fine, expensive opals
in jewelry except perhaps into rings where they may be subject to too
much risk of damage.

Daniel R. Spirer, GG
Spirer Somes Jewelers
1794 Massachusetts Ave
Cambridge, MA 02140
617-491-6000
@spirersomes
www.spirersomes.com


#4

I have heard from stone cutter two different comments on opals.
One is if it is gonna craze it is gonna craze no matter what.
Another says that hethinks he has a large piece of opal “healing” in
jar of water. That the crazing is going away. I don’t know if
either is correct. I have set numerous pieces of opal crystalline
and boulder and I love them all. they definitely need to be used
however fragile they are. Wear it until you notice a problem,
THEN, turn it into a display piece if necessary. Long live opal
jewelry!


#5

Blain

There are in my mind, two types of opal. The first is the kind one
buys, and it may be either rough OR a finished stone, for the purpose
of pure love of the stone, or in another view, as an investment.
These may be the $3-5k a carat blacks or maybe an outstanding
harlequin that will simply lay around for years to be picked up and
admired now and then but never put into a piece of jewelry and
displayed. They are something private, mysterious even. One note
here, there are few who can afford to purchase this type of stone
(opal or anything else) but now and then someone will simply ‘run
across a great deal’ and can’t walk away from it.

The second kinds of opal are those that may be neither mysterious
nor terribly expensive. I finished cutting one of those a few months
ago. Its a white base but the color is exquisite broad flash at
about a 4.5 and it cut out nice and thick at 22 cts. Not a stone I
would want to sock away in some dark place. Its too beautiful for
that and it is a show stone and is meant to be worn and seen. I’ve
already begun gathering the makings for a very special setting.

By the way, I purchased the rough nearly 20 years ago for $300!
You can’t imagine what it would bring today!!

Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry! @coralnut1


#6

Hi Friends, I wasn’t going to wade in on this, but feel I have
something to add. It is my belief that some opals… even stone
specific, not just locale specific, are prone to cracking and
crazing, and others are not. It may have to do with mining techniques
or the geologic properties of the stone. I don’t believe there is
anything that can be done to prevent a cut stone from cracking it is
predisposed to do so. Conversely, I think if a stone is stable, and
prudent care is taken, it will always be stable.

I have heard in the past that professional opal cutters will keep
cut stones in their inventory for a year to watch for cracking before
they are put on the market. After a year, they can be reasonably
confident the stone is stable. I guess kind of like the delayed
gratification of a vintner or distillery. Still, I have to wonder if
this isn’t a lapidary “old wife’s tale” because most people I know
need to turn inventory back into revenue as quickly as possible.

I also feel that unless an opal is museum quality, it would be a
shame not to share it with the world. Stable opals are not as
dangerously fragile as many people seem to think, as long as they
don’t get banged up and abused in daily wear. To put an opal (or
tanzanite, for that matter) in a ring, one had better have a metal
structure to prevent the stone from being impacted directly.

P.S. While most boulder opals I’ve purchased are sold by the piece,
some are priced by the carat. Of course, the price per carat is below
that of solid gem opal, and takes into account the matrix:opal ratio,
and the intangible “wow” factor. Don’t you think the dealer must have
some benchmark in mind, even if sold by the piece? Otherwise price
differences in two sizes of the same type of stone would be
arbitrary.

All the best,
Dave
Dave Sebaste
Sebaste Studio and
Carolina Artisans’ Gallery
Charlotte, NC (USA)
dave@sebaste.com


#7
    I  have heard from stone cutter two different comments on
opals. One is if it is gonna craze it is gonna craze no matter
what. Another says that hethinks he has a large piece of opal
"healing" in jar of water.  That the crazing is going away.   I
don't know if either is correct.   I have set numerous pieces of
opal crystalline and boulder and I love them all. they definitely
need to be used however  fragile they are.   Wear it until you
notice a problem, THEN, turn it into a display piece if necessary. 
Long live opal jewelry! 

I just have to ask. Why do you characterize opal as fragile? I
have heard more “ignorant” comments about opal, notice, I said
ignorant, not stupid ( ignorant meaning not knowing). There is
something about opal which attracts stories, fantasies, imaginings.
People seem willing to accept the most outrageous comments about opal
as fact. There has been a thread about educating the public. If we
concentrate on educating those who participate in the business,
the public will benefit.


#8
  I have set numerous pieces of opal crystalline and boulder and I
love them all. they definitely need to be used however  fragile
they are.   Wear it until you notice a problem, THEN, turn it into
a display piece if necessary.  Long live opal jewelry! 

Bravo Mary: I totally agree with your idea - unless you are totally
into displays, I think you should enjoy your opal by wearing it. But
then I feel the same way about my sterling silver tableware. I used
it and my good crystal the entire time my kids were growing up - you
know what, a couple of pieces got ground up in the disposal and a
couple of pieces of crystal got broken, but for the most part I still
have the rest of it today (41 years later) and my kids enjoyed eating
with the “good stuff”. Why save things - life is too short and is
meant to be enjoyed.

Kay


#9
 I just have to ask.  Why do you characterize opal as fragile? 

I am curious as to how you would describe a stone that is

1. Not very hard, 5 to  6/12
2. Not tolerant to heat or cold
3. Not tolerant to low humidity
4. Not tolerant to vibrations (IE ultrasonic cleaning)
5. Not tolerant to oil, soap or most chemicals
6. Porous, and prone to staining
7. Not very tough, will knap off sections with little pressure.

I am not sure, but I would think that fragile is one adjective that
fits well.

Opal is a stone that demands to be treated well. When treated well
they will reward the owner with a dazzling display of color and years
of enjoyment. When treated not so well, they can be a major heart
break. Some demand more gentle treatment than others. Some are, well
just too Fragile to be used in jewelry.

Don Rogers


#10
I am curious as to how you would describe a stone that is 
  1. Not very hard, 5 to 6/12
  2. Not tolerant to heat or cold
  3. Not tolerant to low humidity
  4. Not tolerant to vibrations (IE ultrasonic cleaning)
  5. Not tolerant to oil, soap or most chemicals
  6. Porous, and prone to staining
  7. Not very tough, will knap off sections with little pressure.

With all due respect (and I mean that), Don, I feel you’re feeding
the phobia.

  1. I think that’s fairly hard… of course, not like corundum or
    diamond! But also not as soft as turquoise, lapis, malachite,
    fluorite (?!?), which are frequently used in jewelry.

  2. Not tolerant to rapid changes in temperature, or temperatures
    that are basically inhospitable to human habitation. I’ve had opals
    in storage at both temperature extremes without a problem… just not
    shocked by a rapid change. You don’t want to jump off a plane in
    Anchorage, Alaska in February, wearing the opal ring you wore onto
    the plane in Miami.

  3. Hmmm… if you’re talking about an environmental extreme, I’d
    again have to say inhospitable. I don’t think a lot of people in the
    Sahara Desert are wearing opals.

  4. Many stones are incompatible with the ultrasonic. An extreme of
    vibration, not normally encountered in the real world. Ordinary
    vibrations normally wouldn’t be an issue.

  5. & 6. Pretty much the same thing, and also an issue with many
    other stones. I do clean my opals and settings with dish soap and
    water… have never seen an issue. I am also porous and prone to
    staining. :wink:

  6. I don’t agree with the “little pressure” part. Sure, if the stone
    has a knife edge, but a well cut stone, with a bevel on the lower
    edge, shouldn’t be a problem except with abusive setting techniques.
    I’ll often set opals with a hammer handpiece… and have only chipped
    one. That was not due to the hammer handpiece, but the foolish way I
    clamped the setting (with stone in place) into the holder, putting
    undue and excessive lateral pressure on the girdle of the cab.

My feeling is that, as with any gemstone, one must understand the
characteristics of the stone. There are many more stones I’d be wary
of before opal. A stable opal is not as, I’ll use the phrase again,
“dangerously fragile” as people think, and your treatise only
promotes the phobia.

On the other hand, if you succeed in scaring everyone else away from
using opal, that will leave more for me, the prices will drop, and
I’ll have an exclusive on this truly remarkable gemstone. Keep up the
good work! :wink:

All the best,
Dave
Dave Sebaste
Sebaste Studio and
Carolina Artisans’ Gallery
Charlotte, NC (USA)
dave@sebaste.com


#11

I’ll repeat this story

I was taken with a large dress ring with a jet black stone in it, it
belonged to my exe’s mother. “It used to be much prettier!” I was
told. Off it went to a gemmologist . It turned out to be a very large
opal. It was unmounted and recut - the play of color was amazing. The
problem had been caused because the owner wore it all the time, doing
gardening, washing dishes, swimming etc. and the surface had absorbed
a great deal of water with dissolved salts. The water had evaporated
from the stone leaving the salts behind - rather like a kettle
furring up. I have no idea of the value of the stone but it must be
in the tens of thousands of dollars - we are talking about a real
knuckle duster!

Tony Konrath

Gold and Stone
www.goldandstone.com


#12
The problem had been caused because the owner wore it all the
time, doing gardening, washing dishes, swimming etc. and the
surface had absorbed a great deal of water with dissolved salts.
The water had evaporated from the stone leaving the salts behind -
rather like a kettle furring up. 

There is a type of opal called hydrophane that can absorb quite a
bit of water. But it works in reverse of that scenario: it loses its
play of color when it dehydrates and flashes back to life when water
is restored. It’s mainly a curiosity and not a type of opal used
commercially as a gem. The idea of a fine black opal losing its
brilliant play of color for the reasons suggested is nearly
impossible in my opinion. Black opal from Australia is one of the
most stable and least hygroscopic (thirsty) of all opals.

I’ve only been cutting, setting and selling opals for a bit over 40
years, so I probably have quite a bit yet to learn. Still, in all
those years I have not once seen gem-quality opal damaged or
discolored in any way by water or water-borne agents, including
grease or oil, although I keep reading that it happens. I’m not
saying it isn’t possible but you’d think I’d have run into just one
example in that time.

What I have seen, repeatedly, are opals in rings that have been
scratched to the point that their play of color is nearly invisible.
Simple repolishing restores them to their original splendor. Opal is
roughly the same hardness as glass. It is scratched by ordinary dust
made up of minerals like silica. An opal worn while digging in garden
dirt or washing dishes is certain to to be scratched and lose its
polish over time.

The owner of that valuable opal is lucky to have avoided the
disaster suffered by a 1+ carat diamond I took in for a repair job
recently. The owner, also an avid gardener who never removed her
ring, had managed to break a large chunk off the pavilion just below
the girdle. The fine F-color stone was beyond recutting to anything
close to its original size.

Some of the comments about opal I’ve read here the past week or so
have left me pounding on walls and howling at the moon! Any jeweler
who has the chutzpah to sell tanzanite should never, under any
circumstances, complain about the “fragility” of opal! Opal, like
far softer gems including pearls, requires reasonable care in the
wearing and handling.

It is the job of the jeweler to make certain customers are fully and
factually informed about their purchases. To do that, they must
first inform themselves and not endlessly repeat myths as fact. They
should start by studying a few basic books like Fred Ward’s excellent
"Opals," now out in an updated edition. His chapter on “Buying and
Caring for Opal” is a must-read. There are several other very fine
modern books about opal, and I look forward to seeing Orchid
contributor Richard Wise’s new opal book when it is published. He
has written with expertise and authority on many gem subjects.


#13

As an addendum - the stone was not Australian but came from Thailand
(over 50 years ago.) As I rethink the situation it’s perfectly
possible that the surface was dulled by wear rather than absorption -
but the gem cutter I sent it to reported that it was absorption that
caused the problem.

Tony Konrath
Gold and Stone
www.goldandstone.com
tony@goldandstone.com


#14
A stable opal is not as, I'll use the phrase again, >"dangerously
fragile" as people think 

Dave, and all, I love opals, I use them, don’t claim any real
expertise. But I’m very leery of buying “good” (read:expensive)
ones, in part because of a recent experience. I fear that the phrase
"stable opal" is where you can get into trouble. I have a very
pretty, medium-priced white opal doublet with nice fire, the opal
really thick enough to stand on its own, but backed with black
stone. I have had it, unset, for about 8 years. I love my opals, and
admire them frequently. They are stored in aluminum "watchmaker’s"
glass-topped jars in aluminim boxes, in a cool, relatively humid
basement cabinet. Imagine my distress when, about a month ago, this
opal turned up crazed with fractures, now essentially worthless. I
tried opticon on it, hoping to at least use it for myself, with no
effect. If an opal kept in stable, humid conditions for all those
years can suddenly craze, how can we ever feel sure an opal is
stable? No, I don’t know where it is from–I didn’t know enough then
to ask. The loss is far from financially ruinous, but it is
disconcerting, and sad. --Noel


#15
       ....Imagine my distress when, about a month ago, this opal
turned up crazed with fractures, now essentially worthless. I
tried opticon on it, hoping to at least use it for myself, with no
effect. If an opal kept in stable, humid conditions for all those
years can suddenly craze, how can we ever feel sure an opal is
stable? No, I don't know where it is from--I didn't know enough
then to ask. The loss is far from financially ruinous, but it is
disconcerting, and sad.            --Noel  

Noel, I can indeed imagine how frustrating that would be!

You’ve discovered (the hard way) the reason why I’m wary of
combination stones, such as doublets and triplets. Often the backing
material, the cap, or the adhesive used to make such a stone expands
and contracts at a different rate than the Opal. Over time, this
produces stress in all of the layers; and because the slice of
Precious Opal is the most brittle component, it is usually the first
to suffer damage.

There are valid reasons for making doublets and triplets. Some
varieties of Precious Opal are too thin to be cut into solid stones.
Others contain too much water to be stable when cut as solids (most
Spencer, Idaho material falls into this category.) The risk of
crazing in doublets and triplets can be greatly reduced by the use
of adhesives which remain elastic over time. Potch (common Opal) is
a good choice for use as a backing material. Don’t hesitate to ask
how a stone was assembled…and don’t hesitate to walk away if the
answer is vague!

Opal can never be guaranteed 100% stable. The best anyone can do is
to keep all the risk factors to a minimum. Don’t physically stress
the material. Don’t subject an Opal to excess heat or cold. Don’t
-ever- store an Opal in a low humidity environment (such as a safety
deposit box.)

Sometimes, even when everything is done correctly, a stone will
craze for no apparent reason. :-\

I know this does nothing to restore your damaged stone. I wish
that it could!

Peace,
Peter


#16
But I'm very leery of buying "good" (read:expensive) ones, in part
because of a recent experience. I fear that the phrase "stable
opal" is where you can get into trouble. 

Hi Noel,

Sorry to hear about the long term stable opal that turned "bad."
I’ve had a few disappointing “learning experiences”, too. One learns
(continuously) to ask the origins of the material. It is not a
guarantee, but a strong indication of future stability. I’ve had some
memorable losses with “bad rough” I’ve purchased, but had many more
memorable positive experiences with pleased (and returning) opal
customers.

All the best,

Dave

Dave Sebaste
Sebaste Studio and
Carolina Artisans’ Gallery
Charlotte, NC (USA)
dave@sebaste.com