Irradiated Stones--Danger??

GemDaddy · Posted: Sun Apr 02, 2006 3:17 am Post subject: Irradiated Stones--Danger??

What do you think about irradiated blue topaz, I'll admit that I am new to gemstones but have worked in my fathers lapidary shop most of my life (as a hobby) , is it dangerous? I'm used to just making bookends and fab agate sculptures, but have started getting some stones from Thailand, and worry about irradiation. Also who are good suppliers to get stones from? I have been using multicolour.com?? Has anyone taken the jewelry repair and stone setting class from GIA? So many questions from the newbie. Rolling Eyes

Thanks
John

hehheh · Guest

They are supposed to be safe. After irridiation, blue topaz are heat treated to produce their swiss/london blue.

Stones are then "cooled" for their radiation content over a certain period of time to safe radiation levels before they are allowed on their market.

The problem is sometimes people may become hard up for money before the stones have 'cooled' and release the gemstones to the market before the cooldown period.

The safest is to protect yourself by testing the gemstones with a geiger counter. If the thing cries out at a blue topaz, you should be crying for a lead shelter too!

Aussie Sapphire · Posted: Sun Apr 02, 2006 4:48 pm Post subject:

Hello John,

Welcome aboard. I believe that Blue Topaz is a perfect example of treaments going too far. Sure the discovery that irradiation can make these beautiful gems was a scientific discovery with merit. The result has been the the drastic decrease of the price of topaz rough so as to be worth not much more than gravel.

I think in the past most irradiated Topaz in the retail level would have been totally safe but the market today is a bit different. There are many resellers (such as on Ebay) in today's global market - many of them are dropshipping from other countries and never see the goods themselves - they are trusting that their suppliers are doing the right thing (both in disclosure and in safely processing the gems and waiting the required cool-down period before sale). An inexperienced seller may not be aware of these issues and can be vulnerable to an unscrupulous suppliers desire to move these "hot" gems a little faster than is recommended.

I know that most consumers in our market have absolutely no idea that all commercial blue topaz and many fancy coloured diamonds have been irradiated (some other gems also). Some sellers choose not to handle these types of gems - we are one of those (out of principle - just rather not be involved with irradiation if we can help it).

cheers
_________________
Andrew Lane
(Aussie Sapphire)
www.aussiesapphire.com.au

GemDaddy · Posted: Sun Apr 02, 2006 7:19 pm Post subject: Thanks for the info.

Thank you both for your answers, I think I will follow your lead and just avoid blue topaz altogether. Safety first.
Best,
JOhn

Aussie Sapphire · Posted: Sun Apr 02, 2006 10:57 pm Post subject: Re: Thanks for the info.

ROM · Posted: Sun Apr 02, 2006 11:06 pm Post subject:

Aussie Sapphire · Posted: Mon Apr 03, 2006 3:42 am Post subject:

The import regulations are different everywhere - I think every parcel into the USA is X-rayed but not sure about checking for radiation - Maybe, maybe not.

Bulk shipments of a commodity like that are likely to be checked at customs - individual small parcels going through the mail system might not be. Into Australia, not every parcel gets checked. We know this because every now and then some slip past customs altogether with no checks at all. I do not think this is very unusual.

The use of radiation in Australia is very strictly regulated - in some other countries, I do not believe it is so tightly regulated.

I really do not believe there is generally a big danger in buying blue topaz from a reputable dealer. However, we should be aware that radiation is used so a "too good to be true" deal might be something to be wary of.

I know that a lot of silver topaz from Africa is going to China in large quantities - I presume they are doing this treatment there but do not have specific information on this. I would be interested to hear more from others who know more details.

cheers
_________________
Andrew Lane
(Aussie Sapphire)
www.aussiesapphire.com.au

jleb · Posted: Fri Apr 28, 2006 12:23 am Post subject: radiation

My day job is a scientist, so let me hold forth here..

Most of the irradiation treatments done are with cobalt 60 or in a linear accelerator.

Cobalt 60 produces high energy gamma radiation, which is high powered photon ( light ) energy.

Linacs produce either x-ray or beta radiation. They work by accelerating electrons (or protons) down a magnetic field and impact the target. These are particles, not photons, hence the alternative name 'particle accelerator'.

For a stone to pose any danger to an individual, it has to be exposed to a Neutron beam.

Neutrons are neutral (without electrical charge) heavy particles that can lodge in the nucleus of an atom and change it to a heavier isotope. That heavier isotope is unstable and undergoes radioactive decay, releasing energy as it decays into the stable non-radioactive form. The half life of a radioactive isotope is the period of time it takes for 50% of the atoms to decay from their original state.

Take aluminum for example, the stable isotope is Al-27 . Al -31 has a half life of 644 milliseconds, release a beta particle on decay. Oxygen -16 is the stable form, the longest lived isotope is O-19 with a 26 second half life.

Even if the Aluminum or Oxygen in the ruby (Al2O2) captured a neutron they'd be harmless within a week. The only way any stones are going to capture a neutron is to be placed inside a nuclear reactor. I don't think most treaters have that access...

ROM · Posted: Fri Apr 28, 2006 12:53 am Post subject: Re: radiation

Doos · Platinum Member Joined: 16 Oct 2005 Posts: 2604

I read somewhere a while ago that a lot of Topaz is irradiated at a university in Brazil .. forgot the details.

Carrie · Posted: Fri Apr 28, 2006 10:27 am Post subject:

Gemdaddy asked also about the jewelry repair and setting classes at GIA. I cannot speak directly about their training there, I have only heard some rumours. But I can highly recommend the training at the New Approach School at Virginia Beach, Virginia. The training is condensed in short courses and cram packed with great and innovative technique. They also have some very good training videos. Blaine Lewis teaches there by using a video feed right at his bench and blows it up on a screen so you can really see the very tiny techniques. You can learn more at their website www.newapproachschool.com

Hope this helps! (I am not affiliated with the school in anyway. Just a happy former student.)
-Carrie

Doos · Platinum Member Joined: 16 Oct 2005 Posts: 2604

I only hear great things about Lewis aswell. Have a look at ganoksin.com for some great tips from the benches.

GemDaddy · Posted: Fri Apr 28, 2006 8:09 pm Post subject:

Thanks Carrie, and all. That school does look cool. I'll let everyone know how that class at GIA went when I get back from the beach mid June.
Best
GemDaddy

Carrie · Posted: Fri Apr 28, 2006 9:52 pm Post subject:

Yes, please give us a review of your class! I am interested to hear what you think. I believe that Blaine Lewis has taught stone setting to a couple or few GIA instructors. I hope you will have a very good experience there.

Ugh, the beach sounds great right now! Long day at the bench today.

Cheers-Carrie

valeria102 · Posted: Mon Dec 18, 2006 4:24 pm Post subject:

Just saw this thread cited at Pala in their recent article about topaz & radiation.

LINK to Pala

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