Please forgive a newbie question, but why is an opal never to be set
in a closed back setting? And, can anyone suggest a good resource to
begin learning about identifying varieties of opal, cutting opal and
setting opal? I have recently acquired some opal rough through an
estate sale. Some of it is in water, some is not. I have been afraid
to do anything with it for fear of ruining it. A couple of pieces
have been roughed out to very thin flat shapes. The man whose estate
I purchased it from did intarsia. I knew him and would like to honor
him by completing these as he shaped them.
Please forgive a newbie question, but why is an opal never to be
set in a closed back setting?
There are going to be different opinions on this as usual. Open back
with crystal opal will allow color of the backround, skin or clothing
to showin the opal. Closed back will allow metal behind it to reflect
into the opal, yellow gold can make the opal take on an unattractive
yellow tint, white metal can wash out the color…
A common practice is to use a black backround behind opals that
transmit light.
The black backround intensifies the play of color. Put an opal on a
black backround and see how it looks, put it on yellow or white metal
and see how it looks.
I have shown customers how an opal looks on their choice of metal,
and on a black backround, black backround has been chosen every time.
What brings out the beauty is more important than a concept. I had
the most incredible opal I ever had, it was a crystal based opal, a
doublet witha black onyx base. There was a blue and green neon play
of color that that looked like it was floating within the opal and it
was spectacular. The play of color would not have shown up without
the backing.
Sold to a gentleman who owned an art gallery, it was set in a heavy
18kt gold ring.
The problem with opals in a closed back is that they are a soft
stone and the backs are never perfectly flat, so when someone hits
them the high spots hit the back and the stone breaks. that said I
have mounted many in closed backs. trick is to take some mineral oil
and rub it on the back thn put a layerof epoxi in the setting set
the stone in place and wait for the epoxi to set up then finish
setting the opal. as far as I know none of the one’s I haveset have
broken in the 40 years I have been doing it. the epoxi form fits
tothe back of the stone and gives it a very solid support system.
The oil prevents the epoxi from sticking to the opal just in case
you ever need to remove it for repairs later in life.
Claiming no expert knowledge and experience limited to Australian
opal - but was given the following guidelines:
If it is high quality solid opal - don’t back. At the very least,
this allows the client to SEE they’ve got a solid and not a doublet
or triplet, both of which are already on a backing. On the other
hand, opal for use in intarsia may not be top quality, and if it’s
already very thin, you may have reason for putting on at least a
partial backing.
I’ve never seen boulder opal without its backing matrix, which is
very beautiful in its own right. By its nature, it seems boulder opal
is usually freeform, which can make building the setting a PITA -
sometimes I remove a little of the backing matrix using a wet diamond
file to enable a perfect fit. This is easy to do and does not affect
the opal surface at all.
You don’t say where you are in the world, but if there is a lapidary
club in your region, that’s not a bad place to start, and there are
some informative websites, though sometimes difficult to get to
through the maze of anxious to sell you stuff sites!
Good luck anyway, I do love opal - Aussie boulder opal in
particular.
if an opal is bezel set in a solid back setting, you can’t tell if
it is a solid (high value), doublet (much lower value) or without a
loupe triplet (crap).
Janice, I learned a lot about opals from Paul Downing’s books. He
does talk about the different kinds, cutting, valuation, and a bit
about setting. I’m not too sure you can tell just by looking at it
exactly what kind it is. You can easily tell boulder opal from
crystal for example, but it’s harder for a beginner to tell crystal
from jelly, contra luz etc. If you justwant to cut it, and it looks
like high quality material (strong fire, not full of cracks, etc.)
why not get some beginner material to practice on before tackling
it?
I've never seen boulder opal without its backing matrix, which is
very beautiful in its own right.
Having a free form opal may not bet as big a problem as you would
think. If you buy boulder opal pairs you can have symmetry, as the
pairs are mirror opposites in shape
If the customer sees the opal unset then it is not a problem setting
it the way they want closed or open back.
However if selling a piece that the customer has not seen the opal
out of the setting that is a totally different matter.
To repeat myself how does one know if the opal is a solid or a
doublet when the back is closed?
The value difference between a solid and a doublet can be many
thousands of dollars.
Black backing on opals (doublets) to enhance the colour is common
practice, to try and make them look like the best quality. However
soaked in water they de-laminate and look crap.
Quality AUSTRALIAN OPALS are always solids. Black being the rarest
and most magnificent.
Do I only use solids? I wish I was that rich! But when I use a
doublet I tell the customer NOT to get it wet.
To me that is like saying don’t drink and drive.
the point i am trying to make is be honest with your client. i have
found they appreciate explanations of what is what.
i rarely use triplets, and tell the customer they are 1% the price if
they were solids.
Also to start a controversy, the best opals are not sold on the open
market, they are kept by the miners’ for their old age. And sold to
private buyers.
Opals can “never” be set in a closed setting? As I am fond of
telling my students in all kinds of situations, “There are no jewelry
police who’ll come and tell you you can’t.”
I rarely set opals anymore because I have come to hate them. Fire
opal, and kiddies, I do not mean Precious Opal (oh lord how I wish
the nomenclature would be adhered to properly) is an exception and
will always be set open backed, but I have never had an opal break in
a closed back. The only thought I give to opals is all I give to any
bezel setting, which is “opaque is closed, translucent is open”. I
would rather never use any glue mixture in my work ever. But yet
again, I am a starving die-hard with altruistic tendencies. And as to
doublets vs. triplets, toss them both out or better yet, just smash
them with a carpenters hammer.
Do I only use solids? I wish I was that rich! Also to start a
controversy, the best opals are not sold on the open market, they
are kept by the miners' for their old age. And sold to private
buyers.
I like to pay up front when I buy opals, but dealers may let you buy
the opal and get payment later, or return the opal, like diamonds. I
had an argument with a dealer that insisted that I didn’t pay until I
had viewed the opal, which she posted to me.
I’ve never heard that about opal miners, but I’d believe it.
As for opals, I never heard of the open back argument. In fact, most
ofthe jewelry I’ve seen in New England are the closed-back variety,
and Itypically do a close back bezel setting. The last repair I did
for an opal in gold ring, I had to extract broken opal from ring,
re-cab it into2 pieces, set the 2 opals into a pendant, and then make
a new bezel forthe ring. I had to recab a larger, irregular oval opal
doublet into a slightly smaller, egg-shape oval and set that into the
ring. I found there was a piece of patined silver sheet in the
original setting, to makethe broken opal more “blue”. That ring is on
it’s 3rd opal, and the owner doesn’t care that opals are delicate. It
has to be a blue opal, whether it is a nice natural blue opal or a
doublet. I’m not going to argue with the owner.
I remembered a thin Koroit opal that I had to use epoxy on the back
for extra reinforcement, and another one that cracked in it’s
open-backed setting. If it was a close-back setting, I think the opal
wouldn’t have cracked. To me, opals are delicate, and require as much
support as possible. Open back bezels to me seem an invitation to
allow the opal to crack more easy. Anyways, that’s my feeling.
Whether you guys on Ganoksin feel open back is the way to go, go for
it. I feel if a stone needs support, I will epoxy the back of stone
and do a close back bezel to be double-sure. As a result, I rarely
use opals now. I try to steer clear of soft gems.
Another tip - if I have to set a translucent or transparent stone in
a close back bezel, I will use clear chalking in the setting to
waterproof the bezel, so the stone never gets wet or dirty
underneath. After having to make new bezels for clients who had
jewelry that had gotten dirty underneath them, in bezels, I thought
clear chalking would help. It’sbeen years since I fixed the jewelry
and not a peep from my clients, soI know clear chalking works. Clear
silicone glue works well, ad clear epoxy. I set Czech glass buttons
into close back bezel rings, and use epoxy to provide support for the
glass.
If I am cabbing stones with lots of cracks, I will spread superglue
intothe cracks to help hold the stones together. I use superglue to
glue the stones onto nails and then cab them. That is a tip from
Michael Boyd, a very creative lapidarist/jeweler.
Yes, the mystery surrounding opals is great, but because of the
discussion stirred up by question, a little of it has been cleared up
for me. I continue admiring my opal rough and am beginning to see the
difference between my “learner” stones and the ones I shouldn’t touch
just yet. Thank you to everyone who replied.
With a boulder opal the face of the opal is the nice side, and it’s
true that you can’t tell if a stone is solid or not.
In Australia, if you sell something as a solid opal, it better be
one, the maker runs the risk of prosecution if he sells something
that isn’t as advertised.
This is where reputation and trust comes into play. With the opal
design I submitted to the competition, there is no way to inspect
the back of the opals, basically they are back to back. The opals
have a lot of depth, so when someone who knows what to look for
inspects them they will know their value. To anyone without the
experience to tell, they are little more than an expensive pretty
rock.
The value of a solid opal is really worth the money imo, you can get
lost in stones when you appreciate them.
CIA