Thanks for your response Rick. With regards the definitions of the various "diffusions" I would say, have a look at Joel Arem's article in the Colored Stone magazine entitled "Diffusion Confusion". While I did not care for his (radiation damage creating conduits) conjecture at the end of the article, for the most part he did give some good explanation for the lay reader about the various kinds of diffusion.
We could add some thoughts to his material:
While the term "bulk diffusion" has been applied to crystals, it would be better to refer to it specifically as "lattice diffusion" as it applies to the adding of an element into the crystal lattice structure. Bulk diffusion is a much broader term and while it could be said that pouring cream into your coffee is a bulk diffusion process, you can see where lattice diffusion does not apply.
Channel or "pipe" diffusion is much akin to "grain boundary diffusion" Grain boundary is a term BTW that has been around a long time and is generally in reference to metallurgy. In any case these kinds of diffusions are dependant on small openings, dislocations or fissures.
We've all seen dyed chalcedony or dyed quench crackled quartzes that have experienced these types of diffusion treatments. Not just elements, but entire molecules of bug juice can be induced into the material this way. And sometimes it takes a little extra to open these imperfections up, like vacuum when introducing oils or polymers into emerald, or the heating up of feldspar to introduce the raw metals.
For information on the difficulty of lattice diffusing materials into gems have a gander into the Arrhenius' Theories as how they apply to crystals. Just keep in mind that while corundum can keep it's integrity at temperatures above 2000c, other stones like topaz and tourmaline will begin changing their properties at temperatures of only slightly above 800c.
Keep smiling... so those bugs have a place to land.
Joined: Fri Jan 25, 2008 3:46 am Posts: 247 Location: Sydney, Australia
ROM wrote:
Since this thread is generally about topaz, here's a topaz question. Barring detectable radioactivity, is there any test to distinguish irradiated blue topaz (any kind, Sky, Swiss, London) from natural blues?
Bear Williams- SGL wrote:
I would venture to say that well over 99.9% of any blue topaz is going to be irradiated. And if you do have a natural blue, it still would have to be disclosed as irradiated, albeit by nature.
ROM wrote:
Natural blue topazes sell at a premium, especially if they're from Texas, as I'm sure you know. And as a couple of GO members report, premium-priced natural blues are now being found in Australia. I've also been asked by a couple of very reliable cutters to sell stones they claim are natural blues.
Kyriakin wrote:
I thought man-irradiated stones were just exactly replicating what would have happened in nature ... Blue will always be a popular colour, and topaz is a material with few weaknesses. I would have imagined that a rare natural-blue topaz would be quite a valuable commodity - assuming, of course, it's lack of human modification was provable.
Heya all folks,
Couldn't resist... any discussion about blue topaz is bound to have me contributing my 2-bob's worth.
Background info... Here I am at Mt Surprise and at the moment its all about topaz, what being the peak fossicking winter season and the main topaz digging area in Australia, O'Briens Creek, just 40ks out of town.
Personally, I don't have anytime for treated blues. I've got two really nice cut swiss blues in my trays under the counter and they must come out at least three times a day. People are attracted to the colour like bowerbirds... problem is, as soon as you mention that they are treated and the blue isn't a real natural blue, they drop them like hot potatoes! Here its all about natural blues... they are the best seller.
... AND THEY ARE SCARCE. I've dug a mountain of dirt this season and I've probably got about a kilo of topaz of which ONLY THREE STONES ARE BLUE!!! Most of the natural blues that you will buy from dealers are dug up with bulldozers or people paid a bowl of rice a day over in Brazil or Africa. On the O'Briens Creek field its hand digging only. People out at the fields will happily sell you a kilo of good clear cuttable material but try and get a single blue out of them... nope, no way, they'd rather sell you their first born child. They simply won't let go of any blues... they're too scarce and hard to come by.
I guess it comes down to the fact that here you are buying a hand-dug "locality" item and YES, you WILL pay a premium. You go out and try and dig yourself a blue!!!
Regarding the disclosure side of things, if they are a natural blue then they are considered as natural and un-treated. The accepted thought is that they are coloured by a natural irradiation but we don't know whether that is caused by solar flares, a pocket of uranium, or whatever... or whether it happens over the course of a thousand years or overnight. The topaz here is aged at 300 million years!!!!!!!!!
Back in the day, I used to do some "work" on nuclear reactors. The big uns.
Prior to beginning the job, at each location, and upon departure, the Health-Physics personnel would administer what was called a "full body count." You would sit in this recumbent chair and the technician would point a device at your thyroid gland. It would take a few minutes and the device would print out a full color history of your lifetime radiation exposure.
On your way out, H-P would repeat the procedure again and compare the two to determine my exposure while at their facility. This was like a safeguard in case a high exposure was missed by thermo-luminescent dosimeters or daily monitoring with pocket ion chambers. A few months later, the NRC would send me a report.
Back to the bananas. The first time I ever had a full body count, the tech asked me if I ate a lot of bananas. I said yes and he said he could tell by the scan. I thought that was quite remarkable.
wow, bigfish, sounds like a scary job having to have a "full-body count" to check for radiation exposure before and after work every day. yikes. what would happen to you if your scan came back stating you had been exposed?
Back to the bananas. The first time I ever had a full body count, the tech asked me if I ate a lot of bananas. I said yes and he said he could tell by the scan. I thought that was quite remarkable.
-BF
All sort's of food is commonly irradiated. In the case of bananas, it's the potassium content naturally occurring in that food.
You're going to be "irradiated" with or without the food irradiation treatment if you're a bananaholic.
Joined: Wed Feb 25, 2009 5:53 pm Posts: 175 Location: Toronto
The irradiation of food will produce absolutely NO increase in exposure when compared to non-trated food items. They are treated using gamma-frequency irradiation. This is nothing but EM (particle-less... or massless spin-1/boson particled ). It doesn't 'stick around' after, just like eating an apple that's been sitting on a halogen-covered counter doesn't cause you to eat some of the halogen's rays.
:shock: wow, bigfish, sounds like a scary job having to have a "full-body count" to check for radiation exposure before and after work every day. yikes. what would happen to you if your scan came back stating you had been exposed?
Peeps are exposed every day. The NRC allows you to pick up so many millirems in different time frames. If you are a highly specialized individual, whose services are needed badly, your exposure allowance can be "bumped up."
Exposure is monitored very closely and internal contamination, through your nose or mouth is avoided but does happen.
External contamination can be scrubbed off or removed with duct tape and internal is tracked by watching stool until it passes.
There are all sorts of monitoring daily devices however, the full body scan is only given periodically. At the beginning and end of say a refuelling process or if someone is terminated or contaminated.
Exposure is monitored very closely and internal contamination, through your nose or mouth is avoided but does happen.
External contamination can be scrubbed off or removed with duct tape and internal is tracked by watching stool until it passes.
There are all sorts of monitoring daily devices however, the full body scan is only given periodically. At the beginning and end of say a refuelling process or if someone is terminated or contaminated.
-BF
pretty wild that you can remove external contamination with duct tape, bigfish! anyway, please do your best to safe while on the job!!
Users browsing this forum: Google [Bot] and 3 guests
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot post attachments in this forum