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 Post subject: Degree of fading in sunlight
PostPosted: Mon Feb 15, 2010 11:29 pm 
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After Squeaky's post: "What gemstones are affected by sunlight?" and reading about the different gemstones that can be affected, a few new questions come to mind:

To what degree can each gem fade?

Is fading the same for all gems from a same variety or are there degrees of fading depending on source for instance?

If so does anyone have some data?

What kind and length of light exposure is needed to affect the color?

Some mentioned amethyst or chrysoprase as stones that can fade for instance but I have seen some of both that held their colors very well over the years despite quite intense exposure to tropical and equatorial sunlight. I personally have never seen any drastic fading (if any at all) in amethyst, citrine or chrysoprase. I did read that some can fade but never witnessed it.

On the other hand, I have seen some drastic changes in some spodumenes and in yellow sapphires but due to heat more than sun exposuse for the latter in my experience.

Maybe TheGemDr will be kind enough to shed some light on the yellow sapphire fading causes.


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 Post subject:
PostPosted: Mon Feb 15, 2010 11:33 pm 
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:shock: Sorry

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 Post subject:
PostPosted: Mon Feb 15, 2010 11:56 pm 
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some amethyst fade some really don't..have many accounts of amethyst from the diamond hill mine fading in days or weeks where as some JXR material has been left in sun over a year without any noticable fading ..am sure it has to do with the chemical makeup of each individual; stone

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 Post subject:
PostPosted: Tue Feb 16, 2010 12:07 am 
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Thank you for the information Amethystguy!

Do amethysts from the Diamond Hill mine fade to colorless or just become pale?


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 Post subject:
PostPosted: Tue Feb 16, 2010 11:46 pm 
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Hello Lyric,

There's only the one but it was a bit of an involved story. A jeweller client of mine was looking for a guaranteed unheated yellow sapphire, not huge but respectably large. He was getting nowhere with the local gem dealers and I recommended a traveling dealer.

A stone was eventually found and it was then sent to me to recut so that it would fit the customers setting, a ring. I did say to the jeweller that I thought this was not a good idea in view of the reputation that some yellow's have for fading.

The jeweller explained that he had shown several treated sapphires to the customer and told her that they were stable but she was insisting that she have an untreated one, so he was just doing what was asked of him.

Needless to say it came back and bit him when the stone faded and she decided to sue everyone, the jeweller, the appraiser/gemmologist, the stone dealer and me!

Sadly the jeweller took the cheapest, easiest, quickest exit and settled out of court with her. I'm sure my testimony wouldn't have helped anyone's case...grin.

Tony.

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 Post subject:
PostPosted: Wed Feb 17, 2010 1:23 am 
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Hello Tony,


Thank you for your answer and fascinating story about the fading yellow sapphire.

I am sorry that you had to go through the trouble and the lawsuit threat.
It sucks big time especially with your warning to the jeweler not to mention all your hard work with this outcome.

Did the stone fade during the polishing rather than the cutting phase because of the heat?
So this would mean that the sapphire did not fade because of exposure to light if I understood correctly.

As a jeweler I have seen in a workshop a yellow sapphire turn colorless during a heavy ring sizing, although the jeweler had taken the precaution of immersing the part of the ring with the stone in water. I guess it was not sufficient because of the heat generated to solder the seam of such a big ring. The poor man was livid when he noticed.

To this day I will never solder a piece with a stone set in it, not even a diamond. Of course with laser, TIG and all the advanced technology we have other safer options.

Lyric


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 Post subject:
PostPosted: Wed Feb 17, 2010 5:36 am 
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Well now I'm confused.
Tony, was it the cutting/polish that Lyric's thinking or was this some time after the woman was wearing the ring? I would imagine resizing would have been done while the stone was out.

Edit, hmm, you don't mention resizing the ring. :?

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Last edited by mehoose on Wed Feb 17, 2010 7:26 am, edited 1 time in total.

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 Post subject:
PostPosted: Wed Feb 17, 2010 6:15 am 
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hey Lyric,

lyric wrote:
To this day I will never solder a piece with a stone set in it, not even a diamond. Of course with laser, TIG and all the advanced technology we have other safer options.


unfortunately i need to do it more than 1 time a week, even with emeralds, never had troubles in 23 yrs, but it's not an easy task and EVERY time my hairs turns more white... :lol:

ciao
alberto

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 Post subject:
PostPosted: Wed Feb 17, 2010 6:17 am 
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I will never forget the first time I fried an emerald. I worked for free for weeks.

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 Post subject:
PostPosted: Wed Feb 17, 2010 9:48 am 
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Hi Alberto,

I should have been clearer, I will not do it with a large center stone.
Small side stones are OK but I will remove the center, I was that traumatized!
I also don't like this kind of "thrill" but you are right I know a lot of good jewelers that do it and they have not had problems.


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 Post subject:
PostPosted: Thu Feb 18, 2010 2:50 pm 
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Hello Lyric,

No it wasn't me or any heat. The customer wore the ring daily mostly outdoors for a few months before she noticed the colour was fading.

It was almost a year before I found out about the lawsuit and submitted my story to the jewellers lawyer.

Although jewellers know they should never take a chance with a stone they can't easily and cheaply replace, I do get sob stories from guys that start with "I've been doing it this way for years without a problem".

Most jewellers know that Rubies and Sapphires can take heat , not all of them realise that flux will severely damage the polish.

Tony

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 Post subject:
PostPosted: Thu Feb 18, 2010 3:42 pm 
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Hi,

TheGemDr wrote:
Although jewellers know they should never take a chance with a stone they can't easily and cheaply replace, I do get sob stories from guys that start with "I've been doing it this way for years without a problem".


yeah, forget to mention that everytime i strongly try to dissuade people, sometimes they agree, mostly when hearing the words: "...ok, but i wouldn't take any responsability..." :lol:

ciao
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 Post subject:
PostPosted: Thu Feb 18, 2010 9:43 pm 
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Hello Alberto,

I was just reading through the thread again and I realised my comments might have seemed rude. Sorry if it was taken wrong as I did not mean to offend.

However seeing as how you ask the customer first and are told to do these things it makes everything completely different.

Asking forgiveness rather than permission works with wives, never with customers.


Tony.

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 Post subject:
PostPosted: Thu Feb 18, 2010 11:40 pm 
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Lyric,
The experience and opinion of the Aussie mob is that none of us have witnessed Chryso fading, even with 30+ years of normal wear/exposure to our sun.
Chrysoprase will get localised white burn marks during the cutting phase if it gets too hot.

No one has come across our natural sapphs fading in sun.
Our Hart's Range pink Zircons can fade but it hasn't been noticed with our beer bottle colours or reds....do remember Tim's wife experiencing one of her's changing in an earring, just can't remember what colour that was.

There was this experience from Leah( Aussie Sapphire's wonderful wife)
Quote:
We had the opposite experience with heated zircon. We did a few zircon just as an experiment a long while back - heated back to diamond white colour - really flashy nice gems but after some time in the sun or under bright lights in gem trays, a lot of them actually regained colour.

Since the treatment was not stable, we do not heat our zircon. The natural colours are really nice anyway. Havent noticed any fading in sunlight in our zircon but havent really tested it out.

cheers Leah


Here's a link to a couple of articles that you might find useful
http://www.jckonline.com/article/283706 ... _Come_.php
http://gia.metapress.com/content/m376u8554h7v2136/

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 Post subject:
PostPosted: Fri Feb 19, 2010 1:20 am 
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Thank you Tony for the clarification.

What I truly don't understand is how the client could sue you or the jeweler for nature's "wrongdoing" so to speak.
I am not sure that the client had a case or that a jury would have deliberated in her favor.
As you mentioned the jeweler was the one who settled out of court...
I guess he probably feared for his reputation. Even if he did nothing wrong, his reputation could have suffered from it.


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