FMF - Friends of Minerals Forum, discussion and message board

[vic rzonca]

I have heard various opinions about the treatment of topaz, aquamarine, and quartz with radiation to change their attributes, my questions are: do these treated stones have residual radiation-is there a quarantine time after treatment and are different wave lengths used for various minerals?

[GneissWare]

The answers to your question can be easily found on the web...for example, if you google irradiated topaz you will find several helpful links. Here is one:
https://www.jckonline.com/article/287494-A_Blue_Topaz_Christmas.php
(link normalized by FMF)

[Gordian]

It really depends on the type of radiation. If it is high energy gamma rays, which changes the color centers in the material then there won't be any residual. If someone is dumb enough to put the mineral in a neutron chamber then it may be radioactive for a very long time and may not be what you think it is when you get it back.

c.rhodes
PS I just learned something - the do in fact stick the stones in a neutron line - reactor. Neutrons do in fact react with the nuclear level and can "activate" a material and thus cause it to become radioactive. I suspect that the dose rate is not high is not that high during the irradiation. The nuclei that are being changed to other elements are typically radioactive. I know that neutrons damage the matrix - displacement damage - which can change the color properties. Similarly gamma rays can darken the material. These processes are sometime not permanent - displacement damage may be - and heating or intense light might cause the color to fade. BTW I did read that NRC doesn't consider the residual radiation significant to be of long term danger - though as the person that started the thread says - those irradiated by Neutrons are set aside until their activity level decreases.

[vic rzonca]

Thanks Gneinssware-stupid of me not to have done that first-Just printed out the NRC info-very interesting.

[vic rzonca]

I just got home from work and a question came up in my pee sized brain, what are the nucleotides that are produced from irradiation of specimens, not gems, that include other accessory minerals? Can I find that on goggle?

[Gordian]

With Gamma ray irradiation there is no change in the types of nuclei that make up the mineral's chemical nature. Gamma rays interact with the electrons, mostly the outer electrons of atoms and depending on the energy they cause either a shower of photo electrons or Compton scatter and the electrons showers can change the matrix structure - knock-on type dislocation.

Neutrons can interact directly with the nucleus and depending on their energy they can either be absorbed, causing the nucleus to become excited, which can then decay in any number of ways - either via gamma ray, an electron - a beta particle, which means that the nucleus jumps up one place in the periodic table. Quartz. Also, neutrons can cause displacement damage to the crystal matrix which means it knocks a nucleus out of place changing the properties of the nucleus.

Quartz, silicon is susceptible to displacement damage from neutrons - electrons don't do well in high flux neutron beams. The Aluminum in topaz could change to Silicon and the silicon could become phosphorus and they would probably be unstable. My experience with fiber optics is that gamma rays darken the silicon but passing an intense beam through the fiber reverses the effect. Neutrons change the color absorption properties of the material.

c.rhodes

[vic rzonca]

Just for sake of argument, have we become the alchemist of the past, where we bump an electron here and there, and make what we want? Push a "who" and make gold? Is this really possible? I know this I oratory , but this is quite amazing.

[vic rzonca]

Thanks Gordian, I don't surf the web that much, This community offers me the connection to the some of greatest minds in geologic/mineral science, thank you for your response.

[alfredo]

G&G had an article a few years ago about color changes in gems caused by irradiation in the mails. (This was after the anthrax terrorism scare, when the post office was irradiating everything.)

[Gordian]

[vic rzonca]

Brilliant. Thanks.

[Peter]

Vic
As already noted iradiation can be done with different particles and sources.
Topaz was in the old days, and still in some places irradiated by high n from a nuclear reactor. Depending on from what locality (and thereby the minor inclusions and elements) a mineral may or may not have strong induced radioactivity. Topaz from Spitzkopje in Namibia needs to be kept for quite long time after irradiation, before values goes down below safety limits, while from other areas may have no ro negligible induced radioactivity. The past almost 20 years or so linear accelerators have been used to change color of beryls and other gem materials. Pale, light colored aquas of low value from Pakistan can be made look almost like real heliodore and sellers with no scruples may sell them as such. A friend in Russia made a nice bicolor red and green tourmaline from a ugly green. You can make beryls bi or tri colored depending on where you hit the target and if you have different layers between the sourse and the specimen.
I am sure you have seen many Chinese fluorites of man enhanced colors, topaz, beryl, spodumene (colorless to light yellow) becoming orangish pink you name it.

[Les Presmyk]

I am a bit surprised that no one has mentioned the Arkansas smoky quartz specimens that resulted from batches of crystals being run through a plant that irradiates food for long term storage. When they first came out in the 1970's some people swore they were real. Most justified them by saying that when they were resold, the labels would always note that they were artificially irradiated.

This was at a time before folks decided that quartz crystals had healing powers and the Arkansas quartz producers were looking for ways to sell crystals. For a short time there were smoky quartz specimens coming from Arkansas when someone discovered they could be irradiated.

[Peter]

Les, indeed. There was a unscrupulous german mineral dealer coming to all the shows in Sweden in the 80s and selling those, guaranteeing they were real and assuring people my self collected green Himalaya Mine tourmalines were from Brazil, as he KNEW all tourmalines in "Pala" were pink. We almost had him locked up in the polar region in Sweden when he came and stole the best ton of a dump we made for a local mineral show, by removing a giant pocket with calcite and stilbite, transporting several truck loads to the surface for the show opening. He spent all night highgrading.
People like this are everywhere. some disguising themselves, but same.

[alfredo]

Peter, I think you meant "UNscrupulous"? English is such a tricky language ;))