Heat to black diamond

Hello all,

Those of you with experience working with black diamonds - Is it
safe to apply heat to black diamond the same as it is with white
diamonds, rubies, and sapphires? I will be working near the stone
with 14kt easy solder.

Thank you for your help!

Donna W
Huntsville, AL

OK. I’ll jump in on this. My philosophy & work habits now are-- NO–
to heat on the stones you mentioned, unless you know about the
treatments or lack there of. The other night I went to the Golden
Gate Chaptermeeting here in SF of GIA members and the topic of
discussion was aboutglass-filled rubies, still being used in the
marketplace. I was made aware of this issue back six years ago when I
lost a sale for a large ruby to one being sold well below my cost and
saw another at the lapidary shop being re polished unsuccessfully
after a simple sizing. It looked like a crazed marble.

You can read more about this by googling–Antoinette Matlins and a
paper she wrote “Lead Glass-Filled Ruby: A Case Studyin
Misrepresentation and Deception” or Courtney Balzan. This treatment
now covers not just rubies but blue & yellow sapphires. Once the
damage occurs there is no way to undo it. Most diamonds that are
black have some kind of treatment. There is just not enough material
in the natural state to fill the supply & demands. In repair work, I
either take them out or cover with a heat resistant putty for
protection. Plus there is the clarity enhanced diamonds out there,
too. And sometimes that filler will change colors. If the heat
doesn’t get any of these stones, the pickle or prolonged ultrasonic
may. So, I only submerge the part that I had to solder in a small
amount of pickle and soak in the ultrasonic cleaner-turned off. I
usually hand clean and steam gently.

Proceed with care & all should go reasonably well.

Take care, Jo-Ann Maggiora Donivan

Donna- We made a pendant a few years ago that was made of many
little bezel set black diamonds. They were supposed to be a cluster
of grapes. We pre set the dias and then soldered them together. About
10% of them turned color. Sort of a blackish reddish purplely color.
It was actually good for the project but an unexpected surprise. We
used boric acid to protect them while soldering.

I am often surprised at how very heavily included black dias are.
I’d be careful and use some heat shield. slow heat and slow cool. A
laser welder might be a good choice for this though you still would
need to shield the black diamond with something like white out or
white Fimo as lasers like dark stuff.

Have fun and make lots of jewelry.

Jo Haemer

Thank you, Jo-Ann & Jo.

I was able to use a PUK welder from a friend to take care of the
area in question and it worked quite well. I might have to invest in
one very soon, as I can see a lot of very helpful and practical
applications for it.

Donna W
Huntsville, AL

Hi Jo-Ann and others

Jo-Ann’s link in her black diamond post was very informative.

White diamonds have been ‘filled’ for years and have caused grief to
unsuspecting repairers in the early days.

Now non-certified diamonds are routinely removed before repair work.

Recently I bought a mixed batch of synthetic rubies. Flawless to the
naked eye, beautiful and inexpensive. I was hesitant at first because
even though I sell clear Swarovski CZs people were not inclined to
buy synthetic coloured stones.

Clear CZs are not a problem, a customer went on a tour to Canada and
of course diamonds were involved.

After many ladies had spent serious dollars on diamond earrings and
that night they went to dinner, my customer wore here ‘easy set’ CZs
and did not tell. Made the diamond ladies jealous.

Yes folks a $20 pair of CZs look great and no stress about loss or
damage. Think naughty old ladies (aka sexy senior citizens) on
champagne etc. Where were these women in the 1960s, right in the
middle of the happening. Act pretty straight these days so as not to
upset their fairly straight kids. Yes young ones if you knew what
granny/great granny got up to you would be surprised.

Anyway back to the point. I did not say these rubies were synthetic,
nasty word for most people, I said they were lab grown.

What a change in attitude. No deception just explained the basic
process of growing rubies in a lab.

Also told the customers there are 2 differences between these and
natural rubies.

1 These are flawless to the naked eye (I am talking quality

2 About at least $1000 less expensive, isn’t modern science

Sold the last lab grown ruby today.

As Thomas and others have pointed out most of us do not deal with
the 1%. Using quality synthetic stones is one way to keep the price
down. Also 1% also buy inexpensive jewellery. Sold a pair of silver
earrings to a jeweler’s wife for $25. Simple and elegant. Her husband
makes $35K plus pieces.


Making jewellery is cheaper than therapy.

PUK’s are very good for manufacture, but where they shine is

We had a promotion, and I sold quite a few of them. The machine
basically sold itself.

When I can afford one I will buy one.

Regards Charles A.

I am often surprised at how very heavily included black dias are. 

That’s kinda usually why the things are black… :slight_smile:

I am often surprised at how very heavily included black dias are.
That's kinda usually why the things are black... :-) 

Black diamonds are a wonderful example of the power of marketing.

Al Balmer

Black diamonds are a wonderful example of the power of marketing. 

Certainly, Al, their current popularity is an example of that power,
but while their popularity has gone way up, their price has not done
the same, at least not to the same degree, or to the degree that some
other previously fairly ignored stones did after being "discovered"
by the market. (think about white sapphire.

Used to be, they didn’t even bother cutting the stuff. Now…) They
remain relatively cheap, as they’ve been for a long time, and c’mon,
they are kinda cool looking sometimes. When you want a dramatic,
reasonably durable, black faceted stone, not much else comes to mind
as superior competition…