Gemstone treatments: discussion and questions

[cellentani]

I'd like to open this thread to any discussion or questions on gemstone treatments: heat, irradiation, fracture filling, oiling, diffusion, etc.

I'll start by saying that a few of us have been chatting in another thread about the increasing prevalence of heat and irradiation treatment of rubellites to enhance color. Actually, I think 'enhance' is the wrong term, because as I understand it, the cut stones are first heated to colorless, then irradiated to achieve a desirable color. My questions are, the Brazillian rubellites seem to suffer this treatment the most, as opposed to the Nigerian rubellites - is this because Brazil has the facilities to do this and Nigeria does not? When I hear of a certain locale holding out as an exception, I always wonder why. Also, would the heating affect the inclusions in tourmaline, and what temperature is needed to achieve a colorless stone?

There was also discussion of whether irradiation or fracture-filled treatments were preferred on gemstones, so I'd be interested on hearing everyone's opinions.

 

[PrecisionGem]

I have heated dark red tourmaline with a strong brown to colorless with temperatures around 500 to 700 degrees C.

 

[cellentani]

I have heated dark red tourmaline with a strong brown to colorless with temperatures around 500 to 700 degrees C.

And that isn't nearly enough to melt rutile inclusions. Darn.

 

[jstarfireb]

I don't mind treatments like heat and irradiation, especially if the price is right and the treatment is stable.

 

[T L]

I don't mind treatments like heat and irradiation, especially if the price is right and the treatment is stable.

I prefer untreated stones, but some stones I will accept with treatment like minor filling on emeralds, and heated cuprian tourmalines. As always, it's personal preference, and there's absolutely nothing wrong with treated gemstones, except for the prevelance of non-disclosure. I have a big problem with that, and charging untreated prices for treated gems (hello Tiffany & Co.).

 

[jstarfireb]

Good point - disclosure is key! Although at the prices I'm limited to paying, I often don't know if there's been any treatment. I also wanted to say that I actually lean towards treated stones fairly often because of the price (e.g. prasiolite, blue topaz). But for a more expensive stone (emerald, ruby, sapphire, etc.), I'd want to know for sure.

 

[cellentani]

I don't mind treatments like heat and irradiation, especially if the price is right and the treatment is stable.

I prefer untreated stones, but some stones I will accept with treatment like minor filling on emeralds, and heated cuprian tourmalines. As always, it's personal preference, and there's absolutely nothing wrong with treated gemstones, except for the prevelance of non-disclosure. I have a big problem with that, and charging untreated prices for treated gems (hello Tiffany & Co.).

TL, are there certain stones that you would not accept heat treatment on? I suspect you're not a huge tanzanite fan, but if you were, would these routinely heated stones be acceptable to you? What about heated sapphires? And if not, why are some acceptable, and some aren't - is it the high temperature vs a relatively low temp?

And I agree completely (I think everyone does) about non-disclosure!

 

[SB621]

I don't mind treatments like heat and irradiation, especially if the price is right and the treatment is stable.

I prefer untreated stones, but some stones I will accept with treatment like minor filling on emeralds, and heated cuprian tourmalines. As always, it's personal preference, and there's absolutely nothing wrong with treated gemstones, except for the prevelance of non-disclosure. I have a big problem with that, and charging untreated prices for treated gems (hello Tiffany & Co.).

+1 on what TL said.

Before I discovered PS my DH had a sapphire ring for me made and it is heated. I also have a huge blue topaz that is heated and irradiated- but the ONLY reason I bought it was because I had been searching for months for a stone that size and cut and it was very well below my budget so I thought i would just pull the trigger.

However, except for those two exceptions I would much rather have a gemstone that came out of the earth with the color vs. having it treated to be a certain color. I do accept minor oiling on emeralds- to me that seems less harsh then heating a stone.

 

[PrecisionGem]

TL, what about stones that are heated by nature?

I've heard that some of the naturally occurring blue tanzanite, could very well have been brown tanzanite that due to bush fires over the centuries have been heated and turned blue. I believe the first tanzanite found was blue and on the surface of the ground, so quite likely heated by fire. This could be true for many other stones that react to low temperature. Those Tanzanian zircons can be heated over a candle with dramatic color changes.

 

[VapidLapid]

Even I can be heated over a candle with dramatic, though unpleasant, color changes.

 

[T L]

I don't mind treatments like heat and irradiation, especially if the price is right and the treatment is stable.

I prefer untreated stones, but some stones I will accept with treatment like minor filling on emeralds, and heated cuprian tourmalines. As always, it's personal preference, and there's absolutely nothing wrong with treated gemstones, except for the prevelance of non-disclosure. I have a big problem with that, and charging untreated prices for treated gems (hello Tiffany & Co.).

TL, are there certain stones that you would not accept heat treatment on? I suspect you're not a huge tanzanite fan, but if you were, would these routinely heated stones be acceptable to you? What about heated sapphires? And if not, why are some acceptable, and some aren't - is it the high temperature vs a relatively low temp?

And I agree completely (I think everyone does) about non-disclosure!

I don't like tanzanite that much (not a fan), but if I could get a huge beautiful sapphire or ruby, and I knew it was only heat treated (not diffused or lead glass filled), I wouldn't flinch. I would prefer untreated however. I know almost all neon blue cuprians are heated as well, and that doesn't bother me, although the filling of them (a new treatment on tourmaline) does. I think it depends on the species of the gem. I cannot tolerate irradiation, dying (pearls are often dyed), lead glass filling, or diffusion. However, I do respect people's choices to buy such treated gems, they're just not for me. If I loved tanzanite, I wouldn't mind getting a heated one since almost all of them are heated anyways. This treatment, like with cuprians, doesn't seem to harshly affect their value, same with aquamarine.

 

[iLander]

@VL!

Okay, here's a question about irradiated blue topaz; my MIL, in her 80's, wore a blue topaz ring on her middle finger. She developed a malignant skin cancer on that exact spot, and it had to be removed.

Coincidence?

 

[T L]

@VL!

Okay, here's a question about irradiated blue topaz; my MIL, in her 80's, wore a blue topaz ring on her middle finger. She developed a malignant skin cancer on that exact spot, and it had to be removed.

Coincidence?

Blue topaz is either bombarded with electrons (safe form of irradiation) or neutrons (this form releases radiation). Therefore, that's not much of a surprise. All blue topaz in the United States must pass through the Nuclear Regulatory Commission before it's sold. Some stores just stopped selling it because of that.

 

[VapidLapid]

coincidence

 

[iLander]

@VL!

Okay, here's a question about irradiated blue topaz; my MIL, in her 80's, wore a blue topaz ring on her middle finger. She developed a malignant skin cancer on that exact spot, and it had to be removed.

Coincidence?

Blue topaz is either bombarded with electrons (safe form of irradiation) or neutrons (this form releases radiation). Therefore, that's not much of a surprise. All blue topaz in the United States must pass through the Nuclear Regulatory Commission before it's sold. Some stores just stopped selling it because of that.

The NRC? Aren't these the same people that thought hiding under our desks would be enough? Hmmm . . .

 

[VapidLapid]

@VL!

Okay, here's a question about irradiated blue topaz; my MIL, in her 80's, wore a blue topaz ring on her middle finger. She developed a malignant skin cancer on that exact spot, and it had to be removed.

Coincidence?

Blue topaz is either bombarded with electrons (safe form of irradiation) or neutrons (this form releases radiation). Therefore, that's not much of a surprise. All blue topaz in the United States must pass through the Nuclear Regulatory Commission before it's sold. Some stores just stopped selling it because of that.

The NRC? Aren't these the same people that thought hiding under our desks would be enough? Hmmm . . .

What, that isn;t enough?

At least you'll be found under the rubble of your desk wearing blue topaz!

 

[marymm]

a big +1 to TL's earlier post.

Disclosure and pricing are the larger issues to me when I think about gemstone treatments -- as a consumer I like to know what it is I am actually buying, and being correctly informed and advised (and doing my homework) is key to making sound decisions. Just like any other product, if something has been done to change it from its original condition (from the mine, from the manufacturing plant, whatever the product may be), I want to know. If that Mercedes or that microwave or that iPod has been reconditioned, that means something to me as a consumer. It's the same things with gems - if I am searching for a blue sapphire, I want to know if the gems I'm looking at are untreated or if they've been heated or otherwise treated. And, while heat treatments are usually stable, there are other treatments which are not, and as a consumer I could potentially have difficulties later on down the road if I don't know a gemstone has been fissured-filled or oiled or coated, and I don't take the proper precautions when cleaning or having it set, etc.

My personal preference is for untreated gems. That said, I have a sneaking fondness of London Blue and Swiss Blue Topaz - I first fell in love with their colors as a child, and they still appeal to me. (I only wear them occasionally, not daily.) It does seem fairly common knowledge that they are irradiated stones, however, and they are quite inexpensive. And I'm pretty okay with heat treatment; I have several Tanzanites - again, love the color, and kind of fool myself that if they had cooked in the earth long enough, they'd have turned blue on their own. I try not to stray too far out of heat treatment territory only because for me the appeal of gemstones is that they come from nature, and man kind of puts his spit and polish on it. [I feel the same way about food - I'd rather eat the apple as it came from the tree, than "a processed food product containing ingredients originating from apples."]

Mostly, as a consumer, I don't want to be misled by a vendor or salesperson who is selling a stone priced and hawked as if it is untreated but it is not, and it is not disclosed.

 

[babydoll_mini]

I actually have a question about how a tourmaline "should" be heated...
Experts, please help me~thank you!

I have a unheated copper bearing tourmaline that has some grey in it, so I'd like to heat it myself at home...
Is it possible and how? And is it safe to do so?

I don't want to end up with a colorless stone or a cracked stone

 

[cellentani]

I actually have a question about how a tourmaline "should" be heated...
Experts, please help me~thank you!

I have a unheated copper bearing tourmaline that has some grey in it, so I'd like to heat it myself at home...
Is it possible and how? And is it safe to do so?

I don't want to end up with a colorless stone or a cracked stone

This isn't something you can do in your home oven - you need to be able to ramp the temp up very slowly and also cool down very slowly, over a period of several hours. Plus, even though tourmaline can be considered a low or moderate heat stone, it's all relative - the 300-500+ degree temps you'd need are Celsius, so it's still pretty dang hot. Also, there's no one formula for heating tourmalines - different stones will react differently to heat, and some may require a slightly higher temp to achieve a desired color. I know Gene has heated a few; I hope he chimes in.

 

[Treenbean]

I think I will be stating the obvious here but oh well my two cents. Gem collecting like other hobbies have their categories of collectors. Purist vs non purists (with every machination imaginable under those umbrella terms).

In antiques purist are the gold standard by which all others are judged. ie: there is a reason the Philadelphia Chippendale tilt top tea table, with original finish, attributed to blah blah makes 2.5 million at auction.

Apply this thinking to the gem world and we get the rarity and quality is directly related to price equation. The questions arise from here: Who are the experts? Should we believe the hype? What is the demand for items? on and on and on.

Since you can ask more money for an unpolished, banded lutz marble, you will always have people who will sell things with undisclosed treatments. Whether due to their circumstances (ie: very poor countries, with poor people, who mine and provide stones, or Joe Schmo who can make a faster buck) without disclosure.

Solution? Honesty, achieved by reputable dealers (yeah! Pricescope).
Stay ahead of the game? (there is a reason all antique dealers have blacklights) Know the treatment and don't buy stones that are usually treated a la TL.

Other than that I think, as with most of the worlds problems, there isn't a fast fix.

Before I started looking I didn't even know that gems were treated! I blindly bought what I thought was pretty.

 

[LD]

+100 to TL's comments about disclosure - that's the key.

I prefer natural but will accept heated (as, for me, it's carrying on only what nature started and does).

If a gem is heated (i.e. sapphire) and it affects the price, I expect the gem to be priced accordingly or I'll pass.

Beryillium diffusion is something that I don't accept. I understand that it produces some wonderful (fake) colours and that it's stable etc etc but for me, it's one step too far in the messing about process. However, for those who aren't gem junkies then it gives an opportunity to buy a lovely looking sapphire at a fraction of the price that gem nuts like us pay for natural/unheated material! So it has a market - just not me!

I will never accept coating.

I accept irradiation in some gemstones as it's stable and undetectable. I need to also say though that if I had the choice between natural or irradiated, it would be natural.

I will accept oiling of Emeralds.

I have a problem with filling of Emeralds but understand that this is the norm - so I accept it grudgingly!

I do not accept fracture/fissure filling of any other gemstones as I don't believe it has long term durability/stability AND it has a negative effect on price.

Lasering of diamonds is also completely unacceptable to me and I unfortunately bought one (undisclosed) that had this treatment. I wasn't a happy bunny at all and fought to get most of my money back.
_________________________________________

iLander - before Topaz was regulated there was a huge batch in the US (I think in the 90s sometime) that were waaaayyyyy of the scale when tested by a Geiger counter. Consequently, huge amounts were quarantined to cool down before they could be sold and I believe that's when more stringent regulations came in. I think, if I remember correctly, it was limited to London Blue Topaz and (I think) Sky Blue Topaz. So, it might be possible that some of the material was sold beforehand.

 

[PrecisionGem]

I actually have a question about how a tourmaline "should" be heated...
Experts, please help me~thank you!

I have a unheated copper bearing tourmaline that has some grey in it, so I'd like to heat it myself at home...
Is it possible and how? And is it safe to do so?

I don't want to end up with a colorless stone or a cracked stone

I'll check my notes tonight, but I think I have heat the Mozambique material to 585 C which is 1085 F. Your normal oven can't go this high. I ramp up by changing the temperature 100 degrees per hour, hold the stone for 1 hour, then allow the oven to cool by it's self which is about 12 hours. The stone is packed in a crucible and investment powder. There is always the chance for the stone to crack. I have had some stones that were flawless crack, and I've had some with inclusions that didn't.

 

[iLander]

iLander - before Topaz was regulated there was a huge batch in the US (I think in the 90s sometime) that were waaaayyyyy of the scale when tested by a Geiger counter. Consequently, huge amounts were quarantined to cool down before they could be sold and I believe that's when more stringent regulations came in. I think, if I remember correctly, it was limited to London Blue Topaz and (I think) Sky Blue Topaz. So, it might be possible that some of the material was sold beforehand.

Okay, the timing on the bad '90's topaz is exactly right! She bought it from HSN. I always had a funny feeling about that ring and I threw it out after she passed away.

And how is "cooling it off" going to help? It's radiation, doesn't it take thousands of years to "cool off"? It should have been buried in a salt mine somewhere, not sold to nice little old ladies! What the heck?!!

Now, we have inherited a bunch of her HSN '90's topaz, I think I will strip out of the settings and throw it away. Do you think I should? What about the jewelry it's sitting next too? Is it irradiating that too? Are the settings even safe? Maybe it's melt time!

I could take it to a fire station to have it tested, but frankly, it doesn't seem worth it.

Anything else I should toss out? She had a bunch of citrine, amethyst, etc., all from HSN.

 

[LD]

I actually have a question about how a tourmaline "should" be heated...
Experts, please help me~thank you!

I have a unheated copper bearing tourmaline that has some grey in it, so I'd like to heat it myself at home...
Is it possible and how? And is it safe to do so?

I don't want to end up with a colorless stone or a cracked stone

I'll check my notes tonight, but I think I have heat the Mozambique material to 585 C which is 1085 F. Your normal oven can't go this high. I ramp up by changing the temperature 100 degrees per hour, hold the stone for 1 hour, then allow the oven to cool by it's self which is about 12 hours. The stone is packed in a crucible and investment powder. There is always the chance for the stone to crack. I have had some stones that were flawless crack, and I've had some with inclusions that didn't.

Gene - whilst you're looking at your notes, do you happen to know the temperature to heat Kunzite to please? I've got one that was once vibrant pink but is now almost colourless despite being in my safe and not exposed to sunlight ever I was very tempted to put it inside a chicken and cook in the oven but looking at your temperature guide for Tourmaline, I'm guessing that wouldn't work?

 

[cellentani]

iLander - before Topaz was regulated there was a huge batch in the US (I think in the 90s sometime) that were waaaayyyyy of the scale when tested by a Geiger counter. Consequently, huge amounts were quarantined to cool down before they could be sold and I believe that's when more stringent regulations came in. I think, if I remember correctly, it was limited to London Blue Topaz and (I think) Sky Blue Topaz. So, it might be possible that some of the material was sold beforehand.

Okay, the timing on the bad '90's topaz is exactly right! She bought it from HSN. I always had a funny feeling about that ring and I threw it out after she passed away.

And how is "cooling it off" going to help? It's radiation, doesn't it take thousands of years to "cool off"? It should have been buried in a salt mine somewhere, not sold to nice little old ladies! What the heck?!!

Now, we have inherited a bunch of her HSN '90's topaz, I think I will strip out of the settings and throw it away. Do you think I should? What about the jewelry it's sitting next too? Is it irradiating that too? Are the settings even safe? Maybe it's melt time!

I could take it to a fire station to have it tested, but frankly, it doesn't seem worth it.

Anything else I should toss out? She had a bunch of citrine, amethyst, etc., all from HSN.

iLander, if you're really concerned, I'd definitely take the whole lot to be tested somewhere - it would beat blindly throwing out a lot of pieces that may have sentimental value. I bought blue topaz in the 90's too, but have had no ill effects. I've never worried about it, but I guess I'd be curious to know if there was any measurable radiation.

 

[chrono]

The problem is that if the treatment is currently not detectable (although suspected), how can there be disclosure? I do not have an issue with heating but with diffusion and irradiation. Next comes the problem of testing for both, or rather the cost for testing of these treatments usually far surpasses the value of the gemstone, thus it becomes non cost effective for me to purchase heated stones (which could also be diffused or heated then irradiated) and then having them tested. I understand that diffusion, filling, coating, dyeing and irradiation all transform some ugly ducklings into extremely affordable beautiful gems but my preference is for something totally untreated with minor exceptions.

 

[LD]

iLander - before Topaz was regulated there was a huge batch in the US (I think in the 90s sometime) that were waaaayyyyy of the scale when tested by a Geiger counter. Consequently, huge amounts were quarantined to cool down before they could be sold and I believe that's when more stringent regulations came in. I think, if I remember correctly, it was limited to London Blue Topaz and (I think) Sky Blue Topaz. So, it might be possible that some of the material was sold beforehand.

Okay, the timing on the bad '90's topaz is exactly right! She bought it from HSN. I always had a funny feeling about that ring and I threw it out after she passed away.

And how is "cooling it off" going to help? It's radiation, doesn't it take thousands of years to "cool off"? It should have been buried in a salt mine somewhere, not sold to nice little old ladies! What the heck?!!

Now, we have inherited a bunch of her HSN '90's topaz, I think I will strip out of the settings and throw it away. Do you think I should? What about the jewelry it's sitting next too? Is it irradiating that too? Are the settings even safe? Maybe it's melt time!

I could take it to a fire station to have it tested, but frankly, it doesn't seem worth it.

Anything else I should toss out? She had a bunch of citrine, amethyst, etc., all from HSN.

First up, don't panic. There's nothing to say that your MIL's topaz was one of these it could just be a horrible coincidence. I've been trying to find the original literature but I think it was between 1990 and 1993. There's a good article on Palagems if you want to read up on it:

http://www.palagems.com/blue_topaz.htm

and more

http://www.diamondvues.com/2007/07/irradiated_blue_topaz_be_very.html
http://www.couturejeweler.com/nj/colored-stones/article_detail?id=17016

If I find the original press reports, I'll post them up.

Found this - it looks like it was earlier and was in 1970 - here's a cut and paste from an article:

IMPORTANT NOTE: Irradiated gemstones can be radioactive! Distribution of blue topaz is controlled in the United States by the Nuclear Regulatory Commission, due to the fact that radiated blue topaz stays radioactive for up to a year after treatment. And in 1970 a lot of "hot" blue topaz was sold on the world markets. Also, some diamonds also stay radioactive for many years after radiation treatment. One diamond recently tested in a major European laboratory was so radioactive that it would not be safe to be worn for 35,000 years. So be sure that if you are buying a gemstone that could possible be radiated, like blue topaz, colored diamonds, and even chrysoberyl cat's eyes, be sure and buy from a jeweler with a well trained gemologist who knows how to protect your interest of your purchase. This is not meant to scare anyone, but to let you be aware that a well trained gemologist can be an important person to know when shopping for gemstones.

 

[T L]

It should also be noted that London blue topaz (the darker colors of blue topaz), are treated with neutron bombardment. I don't believe sky blue is treated in such a way.

 

[soberguy]

I'm a "purist" I suppose. I despise treatments. I would rather save up and buy untreated if necessary. I don't even like bleached and pinked pearls... That fact that Tiffany & Co has chosen to make use of some "over" - treated gemstones makes me ill... It's hard to explain I suppose, but I think something that nature has made is more interesting than what humans may do to pervert it... There are some gemstones that are heated as a rule, and the only one I really like is Zircon... I quite dislike tanzanite. Anyway, my 1 cent

 

[Lee Little]

I prefer good quality things that last a lifetime and then some, thus if a gemstone treatment is safe for consumers and is permanent then it is a good one by my standards. Regular heat, heat with Borax/flux, and heat with Beryl products are all basically lifetime guaranteed thus I appreciate them. I do not accept any coating that can wear off. Fillers such as those in Emeralds, Jade, and leaded glass Rubies, plus dye in pearls, are only acceptable to me because they look so good for the price and I realize they are short term pleasures. I am very shy about irradiated gems, have never bought or sold the irradiated blue Topaz but cannot resist Rubellite. Of the two kinds of radiation used on gems, I think the Blue Topaz is the possibly dangerous one and the Rubellite is the probably safe one, true or false? Best regards, Lee