Heating diamond

I don’t think you can heat the diamond in the presence of oxygen to
anywhere near that temperature without damage. I have a client who
has bought several diamonds from me and has had them set into her
teeth. The dentist drilled a hole in the tooth and used the type of
bonding material that is set with ultraviolet light to hold the
diamonds in place. Personally, I think it’s a silly idea. Nobody,
including me has the nerve to tell her the diamonds look like cavities.

I don’t think you can heat the diamond in the presence of oxygen to
anywhere near that temperature without damage.

“Although diamond is ordinarily infusible, it may be burnt if
suspended in a jar of oxygen, as Lavoisier first proved. A
temperature varing from 760 deg. to 875 deg. C is necessary to burn
diamond.” from “The World of Jewel Stones”, Michael Weinstein,
Pitman, 1959.

That said, coating the diamonds with a thin layer of roughly ( all
my proportions are rough ) 2:1 borax:boracic acid in methylated
spirit to exclude air and thus oxygen is sufficient to prevent
oxidation of their surfaces - that is, they won’t “burn”. That again
assumes they’re not fracture-filled or otherwise junky crappish

18k Au hand engraved watch case with diamonds, transparent dark blue
and black vitreous enamel - restored with vitreous enamel this week.


Al Heywood

I have pre set diamond and soldered them in place countless times
before today but today something was different - After soldering four
stones in place one of the diamonds looks milky now. I was very
careful - made sure the flux was dry and not touching the stone, also
no quenching.

Any thoughts? Similar experiences?

I was wondering about this too. I’m contemplating a project where I
tube set diamonds first and then solder them in place, and I was
going to ask advice about it here.

Janet Kofoed

Shand- You smoked it. It will need to be replaced or re-faceted by a
diamond cutter.

Diamonds must ALWAYS be covered with fire coat when soldering. It’s
made of denatured alcohol and boric acid. Pripps will do dandy as

In the old days we used to heat and quench diamonds to clean them.
With the treatments available now we don’t do that any more. Just air

Have fun and make lots of jewelry

Jo Haemer

Besides that can I put the pre set diamond in pickle?

You are not giving a lot of However, obviously you’ve
burned a diamond. Boric acid and alcohol will prevent this, to a
point. You can easily go beyond the protection temperature range this
provides. Also, you mentioned not having the flux touching the stone.
Why not? Corundum is subject to boric acid etching under heat, not
diamonds. When tipping diamond jewelry, always have the piece
immaculately clean, and use plenty of anti-oxidizer (Boric acid
dissolved in alcohol) If you don’t get a good solder flow initially,
clean again and re anti-oxidize. Don’t reheat before doing this Your
anti-oxidizer breaks down and doesn’t protect any more.

I had that happen to me once on a repair when sizing a plat. ring. I
knew I did not overheat the stones at the very top of the ring when
I was just doing a sizing. They turned out to be fracture filled. Who
knew or even bothered to check. The ring was right straight from the
vendor and there was no disclosure.


Like you I’ve soldered diamonds in place many times. Stones up to a
carat at times. Larger, expensive ones I check out first for
internal stress. Even so, there’s always some Torch damage risk. A
couple times I’ve run into coated diamonds, probably vacuum
sputtered, that clouded and appeared damaged after soldering (think
they were retipping jobs). Regular pickling easily removes some
diamond coatings but the high-tech films that were applied a couple
cases required strong, hot sulfuric to dissolve discoloration /
surface clouds before returning the diamonds to ‘normal.’ (I’m not
referring to HPHT [diamond] treatment which is very heat tolerable)
Maybe your stone was damaged, maybe not? just some of my

Richard Paille

OK, let’s try this again–my answer went into a cloud.

There isa possiblity not yet mentioned–the milky stone is not a
natural diamond. There are stones coming into parcels that are lab
grown, fractured filled or faux. It could even be a CZ. The fact
that 3 out of 4 were fine and one wasn’t is curious. If all were
treated the same & one comes out frosted- then it can’t be the same

But if you missed with your flame angle, then it is a burned
diamond. In that case, as mentioned before–replace it. If it’s
large enough to re-polish, then do so. If it’s melee, put it into
the damaged pile and sell it for diamond dust. We always coat
diamonds with fire guard (alcohol & boric acid mix) and flux. If the
diamond goes milky–then I overheated it.

Jo-Ann Maggiora Donivan

P. S. Tante grazie to Hauman & Ton for making this forum happen !!
We truly appreciate all thehard work and dedication on a daily
basis. As president and part-time moderator for our neighborhood
Listserv–this task is definitely challenging on a good day. Imagine
doing it on a world platform with English as a second language.

I always flux diamonds to keep oxygen off them when soldering.
Diamonds willburn if too much oxygen gets to them with heat.

I use Handy Flux which I get from my plumbing supply store. Have not
burnt one sense been using it.

I am sorry but I don’t get it, so if I want to do the tube setting
first before solder to the ring, do I let the whole thing cool down,
and could I put it in the pickle? Thank you for your advice.


Yes you can put it in the pickle. Always let it cool down first.

Who knew or even bothered to check. The ring was right straight
from the vendor and there was no disclosure.

Frank- I am so sorry to hear that this happened to you.

Here is an important lesson here that we ALL need to be reminded

Always always clean and loupe, or better yet use a microscope on any
diamond or any precious stone in front of the customer retail or
wholesale and discuss any flaws in the stones or mounting before
taking it in let alone starting work. No matter how busy you are. 3
minutes added to the take in time can save you untold thousands

We live in a litigious world these days.

How many times have we all heard, “How can I tell if you didn’t
switch my diamond? My Grandfather would NEVER buy a flawed diamond,
or synthetic Ruby, for Grandma. He had lots of money and only bought
the very best.” “Well Mam, because here are the flaws we plotted out
on your job envelope while you were standing here a week ago” Once you
work on it you “own” it for the rest of your or the customer’s life.

Jo Haemer

I agree Joe. I used a binocular microscope in my store for years. It
allowed me to see the flaws and show my customers the flaws nut made
me many more dollars when I showed them the bad prongs or lack of
good prong setting byothers. More then paid for the machine many
times over. and made my work and that of my employes much better…