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A diamond question


#1

i was retipping a three diamond ring, not a lot of heat, and now
one of the diamonds has lost all of its luster. its like it was
burnt. its like the total internal structure of the diamond died
and it just looks like foggy glass. i have never seen this before.
why did this happen? was the diamond treated ? and yes it was a
diamond ,not a cubic and i cleaned it. its internal … not
external. can anything be done to bring back the life of the
diamond? can it be sent for irradiation to change it to a fancy
color and would that bring back the life of the diamond ?

thank you in advance
Ruth


#2

Ruth, I have seen a burnt diamond before and it appeared as you
described except the fog was on the surface. I know the jeweler
sent it to be re-polished. If you covered it with flux before you
pu ou use a “little torch” with oxy/acet you can get a flame hot
enough to burn one. I have done this work for a number of years
and never had this happen to me.


#3

Oh dear, you’ve just experienced the jeweller’s nightmare. Yes,
diamonds can “burn”, and that’s what has happened. There are a
number of reasons that this might happen.

From a working jeweller’s experience, the most common is when the
diamond’s surface has not been protected with a coating of flux.
The next most common cause is from a cooler draft of air suddenly
changing the temperature of the diamond’s surface. The zephyr-like
breeze of someone walking behind you as you are retipping the
diamond ring is enough to "burn’ a diamond if it is not protected.

The diamond can only be restored by a full recut and polish.

To prevent such a disaster befalling you again, coat the diamond
with a layer of protective flux. In Australia, we use a thin
mixture of boracic powder and methylated spirits. Mixed to a thin
consistency, this is painted over the diamond then set alight to
burn out the methylated spirits. This leaves you with a thin coat
of boracic evenly over the diamond. when you begin to retip the
claws, the boracic melts into a glassy protective coating. When
you’ve finished, it can be dissolved off in hot water and pickled
to remove any remaining oxidisation.

I’ve also used a proprietary brand of gold-soldering flux called
Auflux quite successfully for the same purpose.

From a gemmologist’s point of view, diamond, when heated will
eventually convert to graphite. Eric Bruton’s “bible” on diamonds
refers to this happening at around 800 to 1700 degrees C. He goes
into a lot of detail about this in Chapter 19, pp 421-442,
describing the processes that cause the surface to “burn” to a
frosty-white appearance. (Bruton, Eric FGA (1979) "Diamonds"
N.A.G. Press, London.)


#4

Dear Ruth, Sounds like you have heated a "clarity-enhanced"
diamond. My understanding of the enhancing process is that the
stone is impregnated with a low melting temp. glass or some clear
polymer substance. The temperature to retip a diamond exceeds the
temperature of the “fill-in” material. Ibeleive that you can send
off the stone to Yehuda Diamond (I think that what its called) or
some other house involved with clarity treatment. You can find
these guys listed in the JCK 's “yellow pages” . Try calling JCK
directly or the MJSA for listings of these service providers. I
have been living in mortal fear of coming across one of these
stones; as it is not readily apparent to even an experienced
jeweler. Sorry that you have had to experience such a thing!
Good Luck Eben Lenz


#5

Dear Ruth: Sounds like the diamond is frosted. This happens if not
enough flux and too much heat is applied. You can try to have it
repolished by a diamond cutter. It should not be to expensive, at
least cheeper than replacement. I have never seen the internal
clouding appear with tipping, so I suspect it is external. Hope this
help, Janine in almost sunny California


#6

Hi Ruth: A very intersting problem, why don’t you give more info
about the size and clarity before you worked on it, that might
help, could it have been a doublet of some kind, I had a large Blue
Stone someone tried to sell me and it kept testing positive to
Diamond and it was not, it was treatd on the surface with diamond
coating or something that made it test positive.

Happy Holiday!
Chris
http://www.tace.com/glitters


#7

A burnt diamond can be repolished at a cost of 60-100/carat. The
stone should not damaged internally. I have burned more than one
in my time. The only time I affected one internally was when I
quenched a one carat stone and turned an SI stone to an I.

Bruce D. Holmgrain e-mail: @Bruce_Holmgrain
http://www.goldwerx.nu phone:: 703-593-4652


#8

just a quick addition to Eben and Kelly’s post about the fracture
filled diamonds. In Australia we’ve had some problems with these -
both technical, as Eben described, and moral. Our Gemmological
Association of Australia has identified a number of ways to detect
these stones as has your GIA. The moral problem arises when the
stones are resold and the new owner may be unaware of the fracture
filling. Some have been less than honest about selling these and
the jeweller at the bench often has to wear the disastrous
consequences. I feel for you. Rex from Oz


#9

Ruth, it has been treated most likely with a filler . What
happened was the resin cooked! It happens, sorry bout that!! Matt