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Change of color in diamond?


Hi Everyone! Hope you can come up with some ideas that happened to a
piece of jewellery I made. Here’s what happened: I was commissioned to
make a custom ring using the customer’s opal (very nice) I cast the
main part of the ring and fabricated the bezel (in 10K) added a 14K
white gold plate to part of the ring and bead set four diamonds.
The ring turned out fantastic, my client was really happy. About a
week later I get a call from her and she says one of the diamonds have
changed color! I told her to bring it in knowing that she probably got
some mustard ect. under the stone, no problem! Wrong answer, I’m not
sure what has happened although I have a few ideas. First off, I
supplied the diamonds; my wholesaler I trust. The diamonds were an F
color SI1 stones, now the .04 ct looks like a deep yellow turning
towards brown. When I was drilling the holes to the stones I broke
off a drill bit in the ring, I eventually was able to grind out the
balance of the bit but if I missed any would that rust and discolor
the diamond? I have soaked the ring in soap and water and tried to
reach under the stones with a toothbrush but can’t seem to get any of
the discoloration off.

If you have any ideas on what happened please comment!

Thanks in advance, Perplexed in Vancouver, Tara


Hi Tara, you’re most likely correct about not getting the drill
completely out of the whole. You can try soaking in heavy Alum -water
solution for a day or two . Even hold jar with alum in ultrasonic.
That’s all that comes to mind right now. Jeffery Lomax


Hi Tara,

You said that you broke a bur when you were setting the diamond. A
small piece of iron or steel has oxidized in the hole under the
diamond. You have iron oxide under the diamond and probably on the
surroundings of the hole. You should put the ring in a sulphuric acid
solution(70 to 80 %). It will dissolve the steel in few hours and will
not damage the ring. Then, you just polish the ring again. You could
also use nitric acid but is more dificult to control. Good luck.
Christo Kiffer from Brazil


I have been cutting diamonds for 25 years now and I have only seen
one diamond increase in a yellow color from the rough so I feel fairly
certain that you didn’t change color. I have set allot of stones that
for several reasons(polishing compounds, dirty stones not cleaned well
before using a torch and yes even small pieces of broken drill bits
rusting) appear to have changed color. My little secret is I put a
small drop of nitric acid on the top of the diamond if you are able to
with the other stones in the ring, and let it soak in for a couple of
minutes and then reclean. But there are those times you might have to
remove the diamond and really clean diamond and setting area. Scary
but happens to all of us. Hope all works out. Ron Kreml


Tara, Some time back there was a tip on Orchid about getting broken
drill bits and taps out of gold. I believe it was as simple as put
the item into the pickle jar for a few hours and the drill/bit will
simply desolve. The very next week…I broke a tap in a small solid
bead and…sure enough, the tip worked like a charm. Only problem is
the pickle is shot afterwards and must be discarded. By the way, the
pickle should be hot.

Cheers from Don at The Charles Belle Studio in SOFL, USA where simple
elegance IS fine jewelry!


soak the diamond in pickle or a weak hydrochloric acid solution…i
would think that the iron ions are bonding to the diamond…staining
it…always …if you break a bit soak it in an acid solution and
let that dissolve the bit…i would think that there is some of the
bit left in the


OK, I’m not one to really listen to, but if it’s rust, you should be
able to drop it into an acidic solution and have it be dissolved.
Some of the dip-in jewelry cleaners should work, I think. CLR should
work, at least it does in the commercials.

I’d be more inclined to think that the stone isn’t a diamond. You
should be able to test that easily.

This is guesswork for me. I really have no knowledge to base any of
this on.

  • darcy


Several Years ago when I was a much younger GG a store whom I worked
for had this problem, only to make things worse rather than bring the
stone back to the store, the client hired an attorney. After being
asked my opinion I felt that a coating of some kind was the cause of
the yellow coloration. I am told that the plaintive attorney almost
fell out of his chair when the diamond was removed and cleaned in
front of him under court order. Needless to say that he dropped his
suite at that point. Tara, I would suggest that you remove the stone,
clean it a scrubbing powder like ajax or commet past in the palm of
your hand would probably work, if not then I would suggest acids.