My wife is a garage sale junkie and last night we were sorting out
the stuff that she thought was gold for a melt down today. One of
the pieces, (a ruby tie tack) was clearly a cut above the rest and
nicely mounted so I took the trouble to try scratching it with a
piece of quartz that was handy and it was not even close. So, I
presume it is corundum.
Knowing nothing about this piece, there is always the possibility
that it is a natural ruby but the chances are so remote that it’s not
worth paying to have it appraised, right?
I was told that the only difference is that natural usually has
inclusions and this has but Rio Grande says their synthetic has minor
inclusions.
So, just how does an appraiser determine if a ruby is synthetic and
why should one believe him/her?
On another note, my wife was left a ruby ring by an aunt and an
appraiser said it was synthetic and the stone worth about $200. It’s
an emerald cut about 5x 7 mm. How can this possibly be worth $200?
The rough can be had for about $5 retail.
I also note that synthetic ruby cabs can be had for less than a
dollar from Rio and Tripps.
What goes here?
js
http://schmidling.netfirms.com
I cannot tell you how to distinguish between synthetic and natural
rubies. I can address the question you have regarding the valuation
of the by the appraiser:
There are a number of producers of synthetic corundum - the best
known being Chatham (http://www.chatham.com). Chatham’s prices for
rubies ranges from $240.00 per carat to $900.00 per carat (retail)
depending on quality and size. There is now a producer that is
creating corundum of a quality that can be as good as the best that
Chatham offers at prices that are astoundingly low.
From one supplier the price for rough ruby is as low as 6 cents a
carat to as much as 6 dollars a carat. If you purchase the same
stone as cut stones, the price jumps to about 10 times the rough
carat price. The pricing of the rough depends on the process used to
create the rough with flame fusion being the cheapest and
hydrothermal being the most expensive. The appraiser may not be
aware of the newer materials and thus basing the value of the Chatham
gems.
I have personal experience with the newer materials; I just finished
a pearl and ruby necklace for my wife that uses a 15.5 carat ruby
heart for the centerpiece - the ruby, according to the jeweler that
set it, has no inclusions and is excellent in cut, color and clarity.
Using the Chatham pricing, the stone should retail for almost
$14,000 - I paid $11.99 for it. The jeweler compared a 1 carat
padparadsha I had with one he has from Chatham and stated the stones
were identical in cut, quality and color - He paid $180.00 for his
stone, I paid $1.39 for mine. He was completely unaware that the
lower priced stones were available.
I do not think the extremely low prices will continue for long since
the actual producer has supposedly ceased production of corundum for
at least a year. Speculation is that this is being done in an
attempt to increase the price in the future.
Glenn Vaughn
Hi Jack,
I was told that the only difference is that natural usually has
inclusions and this has but Rio Grande says their synthetic has
minor inclusions.
If you really want to know if the stone is a natural or synthetic,
take it to a practicing gemologist with a G.G. or FGA. Rubies were
the 1st gem stones to be made synthetically, back in the late
1800’s.
The fact there are inclusions in the stone doesn’t indicate whether
it’s a natural or synthetic, both can have inclusions.
FWIW: There are 3 different ways to make a synthetic corundum, each
with it’s own tell tale signs.
Dave
I do not think the extremely low prices will continue for long
since the actual producer has supposedly ceased production of
corundum for at least a year. Speculation is that this is being
done in an attempt to increase the price in the future.....
That is a mighty strange strategy if he is the only producer of the
stuff. All he has to do is price it so there is no incentive to by
Chatham. He does not have to give them away and would have
difficulty selling for more than Chatham so I suspect there is some
other problem there.
js
http://schmidling.netfirms.com/weekly.htm
Scratching with quartz basically tells you nothing except that it’s
harder than quartz! Scratching is NOT a recommended test, since it is
destructive. There are numerous clues to differentiating between
natural and synthetic corundum, but you must use a combination of
them to make a clear disinction. (Gemology training and experience
both help.) Re: appraiser telling you synthetic was worth $200. It is
likely that you had an unqualified appraiser. Even a high-end
retail jewelry storewould be unlikely to sell that for $200 at full
high retail, unless it included a gold mounting.
David Barzilay
Lord of the Rings
607 S Hill St Ste 850
Los Angeles, CA 90014-1718
213-488-9157
I cannot tell you how to distinguish between synthetic and natural
rubies.
G’day. during a jewellery course many years ago, the class was
provided with two similar rubies. We were told that one was natural
and the other MIGHT be synthetic. Our task was to prove if either
was synthetic. We applied all the usual tests, but had to admit
failure. We showed one had a small amount of inclusions, but the
other one had none. The teacher placed the rubies in a liquid of
the same refractive index as corundum, and then we saw that in the
one with no inclusions there was a faint swirl of red colour, and he
informed us that this was because that ruby had been manufactured by
the doped aluminium oxide power and oxy hydrogen flame process, with
the crystal being built up from the vapour on a rotating zirconia
pedestal. Hence the pale pink swirl pattern. He brought out a third
ruby which had inclusions, but it also had the faint swirl. He
pronounced it synthetic because a friend in research had made it for
him when he was overseas. Tricky, eh?
Cheers for now,
JohnB of Mapua, Nelson NZ
How can one distinguish a Chatham stone from cheaper lab corrundum?
Jeanne
http://www.jeanniusdesigns.com
Scratching with quartz basically tells you nothing except that
it's harder than quartz!
On the contrary, it told me that it is harder than quartz which is a
useful bit of info at that point in time. A red stone that looks
like a ruby and is harder than stone is not junk.
Scratching is NOT a recommended test, since it is destructive.
It was headed for the junk pile and this was just a detour. Not
being able to scratch it, told me that it is not junk all else
considered.
Re: appraiser telling you synthetic was worth $200. It is likely that
you had an unqualified appraiser…
My sentiments exactly. Thank your for confirming.
js
http://schmidling.netfirms.com
How can one distinguish a Chatham stone from cheaper lab
corrundum?
Very good question and one I cannot answer. I am sure there is a
way. My jeweler had one of each in hand (2 padparadshas) and could
not tell the difference even with the loupe.
Glenn Vaughn
The reason I ask is that there is such a difference in price when
you buy them, but if you can’t tell the difference afterwards, what’s
the point? I also have gotten a bunch on auctions at time and I don’t
know how to price them.
Jeanne
Jeanne, IMHO, this is always the ‘problem’ with synthetic OR
imitation vs. natural gems. There is almost always a HUGE difference
in price, and it is a personal decision by each client whether it
matters to them if they have real or imitation jewelry !
If it doesn’t matter, then CZ is as good as diamond, and flame
fusion corundum is as good as a fine natural ruby. I, personally,
do NOT believe that is so. You and each client must decide for
yourselves.
BTW, CZ is not as good as diamond ! The phrase: ‘a diamond is
forever,’ is mostly true.
Cubic Zirconia isn’t even CLOSE in longevity (they’ll show wear in
short order) but they’re much cheaper…which do you want?
David Barzilay
Lord of the Rings
607 S Hill St Ste 850
Los Angeles, CA 90014-1718
213-488-9157
Your cheaper lab grown synthetic ruby could probably be flame
fusion type i.e. Verneuil synthetic ruby. It is much cheaper to
produce and has been around (as someone has mentioned since late
1800’s and beginning of 1900’s). Flame fusion ruby could be
differentiated from the Chatham or Russian Flux grown ruby is by
their inclusions or certain growth marking. The Verneuil synthetic
ruby would show a curved striation growth marking with some gas
bubbles. Whereas Chatham flux grown ruby would show wispy-veil
growth marking which is rather unique because these grown marking
are residue of the flux material. Sometime you may come across
platinum platelet inside the Chatham synthetic ruby as they use
platinum crucible for their growth process. Occasionally, some
Chatham synthetic ruby could give rise to problem in identification
especially when the wispy-veil may exhibit a look alike healed
fissures found in natural ruby. It is best that you try and read
up the classic reference book on ‘Photoatlas of inclusions in
Gemstones’ by Dr. E. Gubelin and Mr. J. Koivula; ‘Gem Testing’ by
B.W. Anderson; ‘Handbook of Gem Identification’ by R.T. Liddicoat.
The subject of gem identification is too wide a subject to be
discuss in here and my simple advice is to read up, cross check with
gemologist and hand-on experience. Good luck to you.
Tay
Singapore
Google search: tay thye sun
I think the inclusions I was seeing with the hand lens were just
detached adhesive as I don’t see them under the microscope after
cleaning it.
However, what I do see are lots of bubbles, mostly long skinny ones.
At every level of focus these are visible. I do not recall which
type of synthetic this would indicate but I have never seen any
bubbles of any sort in the several boules of flame fushion I have
purchased.
Just for fun, I took a picture of it and posted it to
http://schmidling.netfirms.com/rubyinc.jpg
js