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Ever bought a gem that later lost its color saturation?

RedSpinel

Shiny_Rock
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Apr 28, 2012
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211
In 2006, I found some great looking African Hiddenites from an online Thai dealer that I had bought from at least once before, and he had recently been getting these Hiddenites in stock for the first time that I had ever seen. He had several of them ranging from approx 9cts to approx 38cts. So I bought a 33ct Hiddenite from them, and when I received it, it looked a little lighter than in the advert pictures. This dealer always showed his stones using video on a turntable most of the time, as well as pictures from different angles.

Aside from the lighter color, I was happy with the stone. It was very clean, bright, and I liked the color. I found a large gem box to store it, because my standard gem boxes were too small(you can see some in the background in the photos). Then I stored my collection in the usual place where there is darkness. I brought out the collection just about every day to look at the new stone and others. But then I quickly began noticing that the Hiddenite appeared to be lighter in color than before. At first I thought it was just an illusion, but it became more obvious as the days past. Then after about 2 weeks or so, the color was much lighter, although you could still see the green in the stone. Its box didnt fit into either of my frames, so I kept it separate, and I didnt look at it for about a month or two because I was disappointed. Time went by, and eventually I brought it out again and by this time there was really no longer any hint of green tint left in the stone!

Here are the pictures shortly after buying it, as these are the only pictures I had taken of this stone. I also included pictures taken just a few weeks ago of that same stone. Amazing the difference huh?

BTW: in the earlier pictures, in separate gem boxes in the case that the larger box is sitting on you can see a radiant emerald cut Tourmaline to the left of the box, a pink Spinel to the right, and 2 Rhodolites and another Tourmaline above it. You can see the corner of a box containing a matched pair of yellow Beryls. The stones in the box with the Hiddenite are a dark-ish blue Spinel and 2 Kunzites.

Here are the before and after pics of the Hiddenite..... :(sad

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T L

Super_Ideal_Rock
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I do know that some aquas, morganites and kunzites do lose their color saturation due to light, and the fact they were irradiated. Not sure if hiddenites (which are also spodumene like Kunzite), also lose their color, either naturally or due to some treatment that is unstable.
 

evergreen

Brilliant_Rock
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Jan 18, 2012
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514
In kunzite, if the manganese concentration is sufficiently high enough, irradiation will turn the crystals a deep green. Afghan kunzite is often treated this way and sold as "hiddenite." This is a false hiddenite, as true hiddenite is actually spodumene colored green from chromium, and that green is very stable as the Cr+3 ions are slow to reduce. The green from Mn+4 is not stable, as Mn+4 is easily reduced to Mn+3 and Mn+2. The Mn+4 green kunzite crystals will typically very rapidly fade to purple or pink depending on the total concentration of Mn in the crystal. In crystals with a high concentration of Mn, more ions can remain in higher oxidation states, meaning the colors can last longer.

...from Alnitak in https://www.pricescope.com/forum/colored-stones/chicken-kunzite-t153988-60.html -- the "chicken kunzite" thread. Much more about fading hiddenite follows Alnitak's post, about 2/3 of the way down the page.

Sorry. :(sad
 
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arkieb1

Ideal_Rock
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TL|1396032688|3643014 said:
I do know that some aquas, morganites and kunzites do lose their color saturation due to light, and the fact they were irradiated. Not sure if hiddenites (which are also spodumene like Kunzite), also lose their color, either naturally or due to some treatment that is unstable.

+ 1 - I have seen kunzite change colour over time or on a hot day in the sun and have owned a morganite where the colour seemed to drain out of it over time. Some cheaper stones that are dyed and/or irradiated can and do fade over time. A lot of stones coming out of China and Thailand have been treated. My MIL has non polished non faceted natural pieces of hiddenite as mineral specimens in her shop I can ask her but I don't think I have seen any of them lose their colour over time and they are out under bright shop lights a lot of the time.
 

RedSpinel

Shiny_Rock
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Apr 28, 2012
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211
The 2 Kunzites in the box with that so called 'Hiddenite' have not lost any of their color and I have had them for at least 8 years. I bought a decent refractometer quite a while ago, and I checked the refractive index of every stone I own. I recently re-checked the Hiddenite, and it has the exact refractive index of Spodumene. So, ahhh, maybe its either colorless Spodumene or light Kunzite, who knows..... At least I didnt pay a whole lot of money for it! Shoulda sent it back, but as I recall there was a limit as to how long you could keep a stone before returning it, and I had allowed that time to pass as I kept checking the stone for lightening... I dont recall ever owning a stone that lost its color saturation.
 

Alnitak

Rough_Rock
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Undoubtedly it was irradiated to make it green. Most of the spodumene from Afghanistan is irradiated and heated to "improve" the color since most of it comes out of the ground very pale. Some of it will retain the color, and most will not. It all depends on the total amount of Manganese and other trace elements in the original crystals. The vendors over there who cut and sell it try to move it fast before it fades, rather than waiting several months and seeing which ones are stable and which will fade. Unfortunately, this gives ALL spodumene a bad reputation for fading, when some will not fade appreciably even after years and years of exposure to normal levels of light.

That said, all kunzite does fade, although some fades so slowly its not noticeable (as long as you keep it out of strong UV light like very bright sunshine). In addition, not all kunzite is irradiated to deepen the color. There is natural deep purple kunzite found in California, Nigeria and Brazil. That said, the Brazilians treat many of their kunzites to even out the color and deepen the color of the lighter material. The problem isn't treatment, it's a lack of disclosure. The stones if treated should be held long enough to gauge the color retention and the treatment should be disclosed.

I've had some Afghan kunzite treated and about half of it faded over a few months, while the rest has stayed a nice purple. My US kunzite from the Oceanview Mine and the Pala Chief Mine in California is all deep pink or purple and the color is very stable.

True Hiddenite gets its coloration from traces of Chromium, just like emerald. Its been found in Hiddenite, North Carolina and Brazil, and a very limited find in Afghanistan more than a decade ago. It does not fade upon exposure to light. The "Hiddenite" from Afghanistan you often see sold online for cheap is just kunzite. The green comes from very low levels of Manganese and Iron in the spodumene. When irradiated, it turns a bright to medium green. However, that is VERY unstable, as you saw. It quickly reverts to a lower oxidation state and while it was likely too faint to see, the color would have been a light pink or purple that would itself then have rapidly faded.

True color-stable hiddenite is very rare and very expensive. If you see hiddenite that is cheap--it's not the real deal and it will fade.

Jeff
 

T L

Super_Ideal_Rock
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Alnitak|1396191601|3643743 said:
That said, all kunzite does fade, although some fades so slowly its not noticeable (as long as you keep it out of strong UV light like very bright sunshine). In addition, not all kunzite is irradiated to deepen the color. There is natural deep purple kunzite found in California, Nigeria and Brazil. That said, the Brazilians treat many of their kunzites to even out the color and deepen the color of the lighter material. The problem isn't treatment, it's a lack of disclosure. The stones if treated should be held long enough to gauge the color retention and the treatment should be disclosed.

Jeff

I have in my possession a very pink saturated Kunzite. It looks like a rose de france amethyst color, so the pink is almost verging on puprle. I've had it for at least a decade, but in a dark box, and I rarely take it out. I wonder if its still irradiated because I hear they fade in the sunlight, and since its never in the sunlight, It has never faded any noticeable amount. It's a very pretty stone, but I'm almost afraid to set it because of fading. I'm also not sure of the origin as I purchased it so long ago. It's a six carat stone. Sorry for the thread jack, but I thought I would add it since this is about spodumene treatment.

tlpurplekunzite.jpg
 

gemandjewelrylover

Shiny_Rock
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Jun 6, 2012
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360
Yes, I bought a kunzite pendant that was a lovely light pink color. It's been in a closed- up, dark jewelry box for 7-8 years, and the last time I looked at it, it had lost a lot of color and was near colorless. But another kunzite in the same box for almost the same amount of time kept its color. I was assuming that meant the one that lost color was treated somehow. :((
 

RedSpinel

Shiny_Rock
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Apr 28, 2012
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211
I have this bad habit of occasionally giving away gems from my collection. I gave away a nice golden yellow zircon around 3cts and a nice blue one of the same size. Anyway, I also gave away an approx 12ct Kunzite to my aunt, and of course that gave me the excuse to buy a new Kunzite to replace it! I now own a roughly 10ct Kunzite that is darker pinkish violet(mostly pink) than 95% of the kunzite I see on the market, and another of approx 12cts(the replacement kunzite) that is fairly light in color. Neither have faded at all from what I can see, and I have had the darker one for about 9-10 years and the replacement Kunzite for at least 6 years, maybe longer. It hasnt lost its color either. However, neither of them are mounted and they havent seen much sunlight over that time period. But that OP hiddenite never saw sunlight and it still lost most of its color in a matter of a few weeks! So, if the Kunzites havent lost any noticeable color in all those years, I am not too concerned about them being unstable(but I will keep them out of sunlight just to be sure!)
 

Alnitak

Rough_Rock
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Unfortunately there is no way to know if your kunzite will fade or not unless you have direct knowledge from testing and information from the vendor on treatment. In general if you can get a darker purple/pink kunzite that has not been treated, it will be fade-resistant. Buy from a reputable dealer who has seen the rough and knows the treatment details.

A good fade-resistant kunzite does not need to be stored in the dark, even though that will help. It just needs to be kept out of extended exposure to direct sunlight. I have a pendant I had made from a California kunzite that I keep in a display cabinet. It gets diffused daylight every day, but the glass blocks UV light. Its still a lovely purple with no color change after more than a year. Stored in a jewelry box and worn as an evening gem, I have no doubt that it would still look good a century from now (How do I know this? There are crystals from the same mine in California that have been on display in museums under lights for nearly a century and they still have their color).

Be prepared to pay more for a good kunzite, however. The cheap stuff is cheap for a reason. Top color Brazilian and California kunzites will sell for anywhere from $50-200/carat depending size, cut and color. My best stones have sold at auction for $175-200/carat.

Jeff
 

chrono

Super_Ideal_Rock
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I am sorry your stone faded; irradiation treatment is not stable on some gemstones and unfortunately, there is no way of telling or predicting other than with the passage of time.
 

Buck

Rough_Rock
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I see this is an old thread, but Im here to the end of it all the same lol

I bought a very large Hiddenite for what I thought was a bargain. Its the one in my profile pic. It did appear a lighter green when I first got it, just put that down to a bit of computer manipulation.

Now 6 months later I have just had it out to send off for valuation. Colour looked the same as when I first received it and after reading this I checked...it was listed as heat treated as the only treatment.

Then I read somewhere if a Kunzite is heat treated they tend to hold their colour better/longer or wont lose it at all in some occasions? When I was reading it I figured if that was true, wouldn't they all be heat treated for this purpose alone?

So sorry yours went clear even with all the care you took with it RedSpinel. I am now a tad concerned because the bargain was still the most expensive stone I have bought today. Ah well, give it a couple weeks and the valuers certificate will set me straight I guess.
 

LD

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Funny you should say this. I once (years ago) bought a large Hiddenite of a beautiful emerald green. When it arrived I took it out of the packing and it smelt like petrol and had a sort of oily coating. Over the following weeks it faded to a pale green and never regained its original colour. The only thing I can think is that it had been treated with something but I have no idea what. I suspect as it’s the same gem you have it may be a similar treatment. I may have written about it on here (not sure).

EDIT: just seen this is a very old thread. I suspect mine was irradiated but it’s now a mint green and has been stable for years!
 

Buck

Rough_Rock
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Hi LD,

This has no smells or obvious coatings. I was excited to see 2 little inclusions off to one side, indicating its probably natural least haha.

I haven't noticed any further fading, and right now I sound like a drowning man clutching a straw lol. Will be sure to tell all of what what the certificate says...
 

remetau

Rough_Rock
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Apr 16, 2015
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53
I have a blue zircon that I bought off of Etsy that has lost a lot of it's color.
 

chrono

Super_Ideal_Rock
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I have a blue zircon that I bought off of Etsy that has lost a lot of it's color.

That's an odd one as I've never heard of blue zircon losing colour.
 

stracci2000

Ideal_Rock
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Years ago I bought a gorgeous minty green hiddenite and a pretty powder pink kunzite. They both faded into a plain old colorless spodumene.
So disappointing! Ah well, you live and you learn.
 

LD

Ideal_Rock
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Hi LD,

This has no smells or obvious coatings. I was excited to see 2 little inclusions off to one side, indicating its probably natural least haha.

I haven't noticed any further fading, and right now I sound like a drowning man clutching a straw lol. Will be sure to tell all of what what the certificate says...

There’s no reason to think it’s not a Hiddenite. Mine went from emerald green to a pale soft apple green and it’s still beautiful.
 

Buck

Rough_Rock
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Thanks LD...something positive at least lol. I am a little nervous on the certification of it, just despise dishonesty for financial gain...but then I believe thats what the whole world is suffering through right now. I am a suspicious man within my character I guess?
 

ForteKitty

Ideal_Rock
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Oct 7, 2004
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Oh my! That’s fascinating. Were you able to reverse it ? Did you figure out the source of the change in your stones?

They weren't completely brown, just brown tinged. But yes, they did reverse! Article said UV turns them brown but I had the opposite happen. Mine were in a safe for a long time when they turned brown, and when I left them by the window, they turned back blue and have stayed blue. It's been a few years now with no color change since. I've been storing them in a box in the room instead of a safe.
 

2Neezers

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They weren't completely brown, just brown tinged. But yes, they did reverse! Article said UV turns them brown but I had the opposite happen. Mine were in a safe for a long time when they turned brown, and when I left them by the window, they turned back blue and have stayed blue. It's been a few years now with no color change since. I've been storing them in a box in the room instead of a safe.

That is so interesting. I’m glad to hear they reversed back to blue!
 

Buck

Rough_Rock
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Thanks LD something positive to think of lol. Still a tad nervous till I get the certification back after reading this thread lol
 
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