Back to Ganoksin | FAQ | Contact

Turquoise doublet


#1

i’d be interested in hearing opinions about “backing” turquoise
cabs.

it seems opal doublets, by using black backings, are made to enhance
the apparent play of color as well as to physically strengthen the
opal portion–so there’s an enhancement that requires a value
adjustment, when compared to a solid opal of similar appearance.

turquoise that’s been made into a doublet becomes physically more
stable but without any enhancement of its color (assuming no other
treatments such as dyeing, impregnation, etc.)

so, would it be accurate to say that turquoise doublets don’t
require a value adjustment, relative to solid turquoise cabs, simply
because the appearance hasn’t been enhanced?

thanks,
bill


#2
turquoise that's been made into a doublet becomes physically more
stable but without any enhancement of its color (assuming no other
treatments such as dyeing, impregnation, etc.) 

I have a detailed article about turquoise on my website. The article
explains factors that go into turquoise valuation. While backing
turquoise cab seems like relatively innocent improvement, adhesive
used to secure the backing does represent stabilizing agent which
changes the nature of the stone.

Leonid Surpin
Studioarete.com


#3

Turquoise is sold by the carat. Backed cabs are heavier than
unbacked.


#4

I’m aware this discussion is about turquoise but I felt this needed
to be brought up as well. Opals and opal doublets are valued as
separate entities. An adjustment to value based on whether there is
backing or not is a valuation relic left over from real estate
methodologies andquestionable retail practices. The differences in
backed and nonbacked opals are so varying that a formula does not
due it justice, nor isit remotely accurate. The problem is the
vagueness of representation of turquoise quality combined with lack
of scientific testing of turquoise makes it hard to verify and
confirm treatment or lack thereof. Another problem is the
declarations made by vendors, “I know this is untreated. I’ve done
this a long time. I just know. I can tell quality etc.” Hardly
scientific in approach. Testing tends to be expensive, compared to
individual stone prices, except with important specimens. Sadly we
must rely on dealers reputations and some Voodoo in our purchases.

Arthur Anton Skuratowicz GJG (GIA)
JewelryTrainingCenter.com


#5

Bill, many American turquoise mines produce a vary thin layer of
turquoise which if not backed is not usable. Such as Blue Gem. I have
cut many thousands of carats of turquoise of which 98% is backed. I
back most of what I cut with JB Weld which I buy at Auto Zone. I back
it by applying a blob of the mixed two part adhesive onto a wax paper
sheet which is taped onto a glass pane. Then the turquoise is
squished down into the JB Weld Blob so that it contacts the hard
surface underneath. This keeps the layer of backing as thin as
possible but gives the stone setter (most of the time the stone
setter is me) a flat surface on the bottom of the stone which is much
easier to set. I set on top of saw dust which is used to cushion and
level the stone. This is an old setting method which my family has
used for 86 years and is very common in Native American jewelry.

With out backing the yield of set-able stone is lower. Backing is
time consuming and has costs associated with it in labor and
materials which must be made up for in the selling price of the
stone. So while the per carat cost is increased the survivability of
the stone while being set and worn is increased. To me that is an
acceptable trade off. The larger the stone the greater the need for
backing, in my opinion. If a large stone is set on a cuff bracelet
for instance the curve of the cuff must be countered some how in how
the setting is made and even still the stone is at greater risk for
breaking while being worn. Backing such a stone is the best way I can
think of to make the stone strong enough for setting in that
instance.

I don’t see how putting a layer of JB Weld on the back of a stone
changes the nature of the stone but I am not a chemist and am
unwilling to subject very much of my turquoise to destructive testing
which it seems to me would be required before making such a
statement. Maybe I am not understanding the statement " changes the
nature of the stone" which is ambiguous. It certainly changes the
weight and the stability of the stone for setting so in a sense that
statement is true.

Sam Patania, Tucson


#6

I believe Gary Roskin discusses turquoise doublets in his most
recent Roskin Gem news report. Always facininating reading.

http://www.ganoksin.com/gnkurl/ep7zs1

I have some in my store with faceted rock crystal quartz tops. Very
pretty.


#7

Hi Bill, lots of good answers but I have to say Sam hit the nail,
according my book.

In the instance of heavily matrixed stones and spider web, which is
very valuable, backing is truly a necessary protectant for the stone
to keep the matrix from cracking and thus leaving the stone a good
size with a solid structure.

Think about it, beautiful little blue dots with a black webbing
running through it, one of nature’s miracle, and if that webbing
came off, it would crumble into bunches of tiny nuggets, I have them
both, the stones and the nuggets, truly amazing. Dee


#8
I back most of what I cut with JB Weld which I buy at Auto Zone. 

Sam,

You are by far more honest than most turquoise cutters. I too use JB
Weld to back turquoise cabs. The old standby is Devcon steel epoxy.
Because it contains steel shavings which adds weight to the cab. A
common term is getting the weight back that is lost during cutting
and shaping the cab.

I had a customer bring me cabs, I think it was purported to be
Bisbee, that they got a steal of a deal on. They easily had a
quarter inch of Devcon on the back. I asked the customer if they
wanted me to grind off some ofthe Devcon so I could use 3/16" bezel
or did the want me to roll a custom bezel. I then educated them on
how their “Steal of a deal” was actually a rip-off…

Rick Copeland


#9

Hi guys, I have also backed (when necessary) with Devcon as a
preference over JB weld. I must admit I never thought of the
difference in the two products as a weight problem. I guess as I only
use it occasionally and I never charge the per carat price for the
stones anyway, I just didn’t give it the proper prospective. I chose
Devcon because a mentor suggested it to me and I was told that it was
stronger, and kept a better bond. Ironically I just purchased some
Blue Gem, and was about to back some of the thinner plate material.
Have I been mistaken all these years? Is JB weld as strong as Devcon,
as that would be my main concern? Of course backing is always
explained to a customer, and preferably shown before it is set. No
different than explaining the difference between a solid opal and a
doublet, or triplet. Not all customers can afford a high end solid
black opal that might cost in the thousands of dollars. I look very
carefully for natural untreated turquoise, and with 40 years of
cutting, I can do better than the novice at being correct. I don’t
have the equipment to dissolve and analyze the residue properly, so I
have to fall back on experience as most of us do when selling,
especially in the mid-price range. If I set a wonderful piece of
spiderweb Bisbee that I have had since the mine access was lost, in
18 and 22kt golds, the stone is not backed because I do ask a much
higher price. As has been said before on this forum many times, the
confidence and respect your customer gives you as the years pass by,
are earned by the honesty and open dealing you provide them with.
Full disclosure is an easy thing to do when you have pride in your
work, and how you have dealt with the public. BUT, be prepared to be
embarrassed occasionally, because speaking as an authority is bound
to find your foot in your mouth every once in a while. Thomas III


#10

thanks sam, i greatly appreciate your in-depth response.

as we know, gia has different clarity criteria for different
varieties of gems–we accept a different degree of clarity
characteristics in emerald than we do in aquamarine so it stands to
reason that we could accommodate other factors that are specific to
certain

thanks again–all the best!
bill


#11

Thomas, I would not expect any differences between the relative
strengths of JB Weld and Devcon to make a practical difference. If
ever put to the test I would expect the turquoise to break anyway.
They are probably so close in their properties to be the same in
providing strength to a given piece of turquoise.

I never considered the weight difference a problem because I do as I
was taught as well, it seems a reasonable way to deal with turquoise
so I had no cause to change it. I try my best to back the stone I cut
as thin as possible and I don’t buy cut turquoise with thick backs
but when I look at turquoise I am looking at the color. When I set a
piece in jewelry I cover the backing with the bezel even if I have to
thin out the backing on a flat lap before I set.

The number 8 I am using lately, old family stock, is not backed and
much of the Blue Gem of the same source is not backed and they are
wafer thin. I ask myself if a really thin bezel, used in order to
make setting really thin turquoise easier, worse than a backed
turquoise? So, I probably have put my foot in my expert mouth on more
than one occasion but that is because I live in the real world of
grays not black and white.

Such philosophy in the jewelry business, No?
Sam Patania, Tucson


#12
as we know, gia has different clarity criteria for different
varieties of gems--we accept a different degree of clarity
characteristics in emerald than we do in aquamarine so it stands
to reason that we could accommodate other factors that are specific
to certain 

The reasons, GIA uses different criteria to assign clarity grade to
different are based on gemstones formation. It is
impossible for some gemstones not to have inclusions, so GIA clarity
grades reflect probability of occurrence of a gemstone with a clarity
grade. In other words it is just as likely to encounter flawless
aquamarine as an emerald with modest amount of inclusions. So by
assigning similar clarity grades, but putting gemstones into
different clarity types, GIA standards communicate an objective
reality.

The same cannot be said about using epoxy with turquoise. Turquoise
is available in sizes and quality so it can be used without any
stabilization. Use of epoxy with sub-standart material perverts
objective reality of turquoise formation and availability. I believe
that even with appropriate disclosure it is still a deceptive
practice.

Gemstone value is based on it’s rarity, beauty, and durability.
Faking any of these attributes renders gemstone worthless.

Leonid Surpin
Studioarete.com


#13
as we know, gia has different clarity criteria for different
varieties of gems--we accept a different degree of clarity
characteristics in emerald than we do in aquamarine so it stands
to reason that we could accommodate other factors that are specific
to certain 

The reasons, GIA uses different criteria to assign clarity grade to
different are based on gemstones formation. It is
impossible for some gemstones not to have inclusions, so GIA clarity
grades reflect probability of occurrence of a gemstone with a clarity
grade. In other words it is just as likely to encounter flawless
aquamarine as an emerald with modest amount of inclusions. So by
assigning similar clarity grades, but putting gemstones into
different clarity types, GIA standards communicate an objective
reality.

The same cannot be said about using epoxy with turquoise. Turquoise
is available in sizes and quality so it can be used without any
stabilization. Use of epoxy with sub-standart material perverts
objective reality of turquoise formation and availability. I believe
that even with appropriate disclosure it is still a deceptive
practice.

Gemstone value is based on it’s rarity, beauty, and durability.
Faking any of these attributes renders gemstone worthless.

Leonid Surpin
Studioarete.com


#14

As do we all Sam, whether admitted or not! Thanks for your opinion
on the two backings. Thomas III


#15

Leonid You are the epitome of foot in mouth. Throwing away thousands
of carats of opal, turquoise, and all the other beautiful stones in
the world that can be salvaged and used in jewelry that doesn’t cost
thousands of dollars per piece. You and everyone else that can call
doublets crap because you can afford the alternative, and more
importantly your customers can, do not live in the real world. In
the world most people live in, (not the 1%ers) we have to scramble
and work hard to maintain the integrity that costs us sales when the
mortgage is due, and our children need school clothes. You casually
cast that aside as if it means nothing except that we are not worthy
to polish your shoes, much less your jewelry. In the 45 or so years I
have been at this I have watched De-beer’s and all the other diamond
gods perpetrate the biggest scam on the world next to war. Oiled
emeralds are the norm for the vast majority of buyers, and they don’t
even know that there are several murders a day at the mine just to
dig those few stones up, I wonder how many a day have to die to get
an emerald that would satisfy Leonid? Then there are heated
sapphires, rubies, tsavorites, and the list goes on. Most mid-price
chain stores sell inferior products even by my standards. When I took
my GIA Diamond Course (aside from a few facts that I could have
gleaned from the internet, if I had had the patience to wait a couple
years), it was about how to spin the flaws into more acceptable
terms. Feathers instead of cracks, etc. Then the monopoly of the
sight assignments, and finally a few years later “Blood Diamonds”!
Then the Aussies show up with their own paying mines, and Russia
shows everyone they’ve got even more than De-beer’s. This is the
foundation that you have built your house upon, It is more of an
illusion that an honestly backed piece of Blue Gem that has some
epoxy coating the bottom, and the same beautiful color that the mine
was celebrated for on top. More importantly the customer has been
made aware and given choices of other stones with appropriate price
differences. Cellini kept his foils a secret, and took the praise for
being clever. All I have ever been after is making people happy while
making an honest living for myself and family, you are not the final
judge and jury for all the standards in all the countries and all the
circumstances, with all the materials, how to mark them, where to
sell them, and most important how much to charge for them. I am very
proud of the fact that I have never triple keystoned anything in my
life. If the hunger to make money is the motivating factor in your
life, it will be unfulfilled, as there will never be enough. So you
keep perpetuating this illusion, all fanatics require purpose it is
how you raise yourself above the peasants. Thomas III


#16

IMO putting a backing on a cab, particularly turqouise, is a bad
idea. You can stabilise it’s height in a setting without adding some
foreign material (other than crushed turquoise) that may create a
problem for the person that may do a repair job later in the piece’s
life. Just use the real thing and adjust your design. I don’t know
anyone that would even consider using a turquoise doublet. it’s a far
cry from opal and comparing the two are like comparing apples and
firewood… rer


#17
When I took my GIA Diamond Course (aside from a few facts that I
could have gleaned from the internet, if I had had the patience to
wait a couple years), it was about how to spin the flaws into more
acceptable terms. Feathers instead of cracks, etc. 

A very revealing interpretation of GIA Diamond Course, - to spin the
flaws into more acceptable terms. That really explains a lot. Alas,
if that is all you learned about not much I can do.

Leonid Surpin
Studioarete.com


#18

dary="have always used JB as do most people I know who back their
stones. The people I know who use it for what I would term proper
use mash the stone down as far as possible in the JB thus making it
very thin probably a mm or so generally. Sam addresses this in his
recent article in Lapidary Journal. It is strictly for strength.
Even good quality turquoise can be brittle and the pressure on a
wheel has cracked many a stone. there are many out there who don’t
use it for this purpose they use it to build up the backs of the
stones to absurd heights to minimize the amount of turquoise used
and to maximize profits because it is sold by weight. I have bought
turquoise where it is built up so thick that I actually grind most
of the backing off just to make it low enough to set in a bezel
properly. As for Leonids statement that any epoxy additive to chalk
turquoise renders it worthless is probably not within the scope of
reality in the turquoise market. I would guess that if treated
turquoise was removed from the market 90% of turquoise or more would
disappear. Many mines routinely treat nearly every thing that comes
out. If they didn’t it probably wouldn’t even be profitable to mine
any of it even the small amount of good quality natural that is set
aside. I personally feel that when used properly JB is perfectly
acceptable I mighty also ad that it is acceptable practice,
especially among Native American Jewelers to pad the bottom of the
bezel with tobacco or now days usually saw dust. I have replaced
many cracked stones in Native American pieces to find a paper thin
layer of turquoise with a lot of saw dust underneath. So for the
sake of purity they may not have used a backing but in the long run
it deminished the durability of the piece. Would a backing have been
a better solution?


#19
IMO putting a backing on a cab, particularly turqouise, is a bad
idea. You can stabilise it's height in a setting without adding
some foreign material (other than crushed turquoise) that may
create a problem for the person that may do a repair job later in
the piece's life. Just use the real thing and adjust your design. I
don't know anyone that would even consider using a turquoise
doublet. it's a far cry from opal and comparing the two are like
comparing apples and firewood.. 

The comparison was simply about the fact that both types of stone
were backed. Turquoise can’t handle heat any better than opal. We all
know that you should remove the stone before any soldering
operations, if that is what the repair requires. The backing is not
going to cause any problems that a stone with no backing wouldn’t
cause. I am not sure why you think crushed turquoise is acceptable,
but to be clear, the comparison was two types of stone with two types
of backing. The outcome being useable gem material, that cannot other
wise be used. We all have prejudices and opinions, and different
places where we each draw the line. Simply because you don’t know a
jeweler that would not use a backed stone, is no reason to assume
that there are not plenty of jewelers that do. I did the art show
circuit for about twenty years and saw plenty of practices that I
disagreed with, but having an open mind allows for learning, and
outgrowing some of those prejudices. Turquoise and opal are very
close to the same hardness, both can and do absorb from their
surrounding atmosphere, both scratch and break quite easily, and both
are (whether by you or not) routinely backed in a variety of ways.
Turquoise has the distinction (I believe) of being the most
adulterated, most imitated, but opal certainly runs a close second.
My particular line is not using anything but natural turquoise. I
don’t believe putting epoxy on the back ONLY, as a strengthening
agent, changes the overall chemistry of the stone. Infusing the stone
with Opticon (an epoxy), or any other type of treatment obviously
does, as do dyes and any other enhancing effort beyond backing.
That’s not to mention all the varieties of imitation turquoise. Opal,
again of course, runs a close second, starting with backing; I guess
your right, no similarities here at all. Years ago the practice, even
at the mines in some cases, of simply treating everything that came
out of the ground was adopted. This caused a great shortage of
unadulterated quality turquoise, then of course the world moves on,
mines are closed owners resell leases, the world becomes smaller and
foreign stones are imported. Those of us who love the feel of cutting
that beautiful blue are left hunting through old collections, very
much like my shop’s, for real turquoise. The vast majority of my
stone is thick enough to be cut without backing, and I only do it
when absolutely necessary. The alternative being throw it in the
trash. I only spend the time to defend my position here because we do
not know anything about each other, other than a brief posting. It is
always possible that you may be capable of giving up a small
prejudice in favor of common sense. Thomas III


#20

Hi Thomas H. Louthen III

and to all the others out there who like to play “The emperor has no
clothes!”

You and everyone else that can call doublets crap because you can
afford the alternative 

Talking OPALS HERE. Being able to afford the alternative does not
stop doublets being crap.

Not being able to afford the alternative simply means you have no
idea where to buy.

Doublets are crap because they eventually delaminate. End of story!

I can buy beautiful solid opals (not black) for under $100, lots of
colour and well cut.

Just buy them from a miner, who is a fellow stall holder, who sells
didgeridoos/yidakis that he makes and plays.

As for heat treated sapphires no reason to buy them, plenty of
quality untreated ones here in OZ.

Buy them from the sapphire mining areas.

Because some people work hard and amass money does not mean they do
not live in the real world.

Perhaps they live in a more realistic world than those who spend for
instant gratification rather than thinking of the future.

Probably got a sub-prime mortgage and defaulted LOL.

If one refuses to listen to someone with a wealth of experience and
demonstration of quality manufacture who willingly shares his
expertise through his blog i. e. Leonid then it is no wonder one
justifies crap gems as “All my customers can afford.”

As for pretense those of us who have a genuine family coat of arms,
granted for service to the crown, find adding a numeral at the end of
ones name an Americanism that is nothing more than a feeble joke. See
we Scots can be as rude as the pretentious Americans.

As for backing turquoise with epoxy I have no expertise in this area
(honest I am) so I will not comment.

As long as the customer knows what they are buying then at least it
is honest.

Just because you have not charged the standard markup on jewellery
does not make you a saint. It probably means you have little business
sense. There is a reason for the prices the trade charges, jewellery
is a luxury good.

Richard