|
|
Post by greig on Jul 25, 2017 10:39:52 GMT -5
I found a spot that is loaded with small bronze/brown zircon. I understand that heating zircon will sometimes change the color to clear or pink (or white if you do it too long). I looked up various reports on methodology and the info is inconsistent. For example, one said 500 degrees for 3 hours and another said stove burner on high for 4-5 minutes. So, I tried an experiment with the stove method and that didn't do much. LOL
Anybody have any advise on heat treatment that I should try?
|
|
QuailRiver
fully equipped rock polisher
Member since May 2008
Posts: 1,640
|
Post by QuailRiver on Jul 25, 2017 11:38:18 GMT -5
Somewhere around here I think I still have a Gemology magazine from the 1980s that has an article on heat treating zircon. I'll look later and see if I can find it.
Larry C.
|
|
|
|
Post by fantastic5 on Jul 25, 2017 11:55:54 GMT -5
Can't help you with the heat tx, but I sure do love the video you did! Thanks for sharing!
|
|
QuailRiver
fully equipped rock polisher
Member since May 2008
Posts: 1,640
|
Post by QuailRiver on Jul 25, 2017 12:11:20 GMT -5
Couldn't find the issue of Gems & Gemology that had the article on heat treating zircon. I'm thinking it was either one of the 1984 or the 1988 issues. I believe I have also seen some of these old Gem & Gemology issues archived online somewhere. Possibly on the GIA site. So it may be worth doing an online search.
However there are a couple of pages on heat treating zircons in Kurt Nassau's book GEMSTONE ENHANCEMENT. According to Nassau not all zircons can be heat treated. But of the reddish brown ones that can, they are to be heat treated in a kiln, surrounded in charcoal (to create a reduction atmosphere) at about 1000C for a few hours. This reducing treatment turns some red-brown zircons blue, turns some colorless, and some off-color. The clear and off-color stones can then be heated again to about 900C, this time with access to oxygen. This oxygen rich treatment can turn some of the clears to yellow, orange or red. And some of the off-color stones may remain off-color but can be re-treated through either or both processes. Also he suggests that a very slow cooling after the oxygen rich treatment may be beneficial.
|
|
QuailRiver
fully equipped rock polisher
Member since May 2008
Posts: 1,640
|
Post by QuailRiver on Jul 25, 2017 12:29:11 GMT -5
Was just watching your video and remembered a guy telling me about he used to surface hunt Zircons at night with an ultraviolet light. Zircons fluoresce yellow under ultraviolet illumination.
Larry C.
|
|
|
|
Post by greig on Jul 27, 2017 17:33:45 GMT -5
Can't help you with the heat tx, but I sure do love the video you did! Thanks for sharing! I have fun making videos of my field trips and for some it shows where to go and what to expect. We are lucky in Ontario to have many good rock hounding spots that are open to the public. Thanks. Greig |
|
|
|
Post by greig on Jul 27, 2017 17:36:57 GMT -5
Was just watching your video and remembered a guy telling me about he used to surface hunt Zircons at night with an ultraviolet light. Zircons fluoresce yellow under ultraviolet illumination. Larry C. Very interesting. I know someone else that uses a geiger counter to find the radioactive hot spots for zircon. For the UV,do you know if it needs to be short wave or long wave? I have a small portable long wave somewhere and I will test these zircon (if I can find it). |
|
|
|
Post by greig on Jul 27, 2017 17:39:46 GMT -5
Couldn't find the issue of Gems & Gemology that had the article on heat treating zircon. I'm thinking it was either one of the 1984 or the 1988 issues. I believe I have also seen some of these old Gem & Gemology issues archived online somewhere. Possibly on the GIA site. So it may be worth doing an online search. However there are a couple of pages on heat treating zircons in Kurt Nassau's book GEMSTONE ENHANCEMENT. According to Nassau not all zircons can be heat treated. But of the reddish brown ones that can, they are to be heat treated in a kiln, surrounded in charcoal (to create a reduction atmosphere) at about 1000C for a few hours. This reducing treatment turns some red-brown zircons blue, turns some colorless, and some off-color. The clear and off-color stones can then be heated again to about 900C, this time with access to oxygen. This oxygen rich treatment can turn some of the clears to yellow, orange or red. And some of the off-color stones may remain off-color but can be re-treated through either or both processes. Also he suggests that a very slow cooling after the oxygen rich treatment may be beneficial. Excellent info and thank you so much for looking for the mag. |
|
lookatthat
Cave Dweller 
Whatever there is to be found.
Member since May 2017
Posts: 1,360 
|
Post by lookatthat on Aug 14, 2017 12:26:22 GMT -5
Nice vid. If you like zircon, check out the Bancroft, ONT area. I found a nice one in matrix in the Bancroft rock pile that's there for collectors.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Aug 14, 2017 13:46:06 GMT -5
greigAmy update? I don't own a furnace so no love from me. Would love to see your results.
|
|
|
|
Post by greig on Aug 21, 2017 10:39:05 GMT -5
Nice vid. If you like zircon, check out the Bancroft, ONT area. I found a nice one in matrix in the Bancroft rock pile that's there for collectors. Nicely done. I have never checked out that rock pile, assuming that it has been picked over for years. I will have to change my mind on that. |
|
lookatthat
Cave Dweller
Whatever there is to be found.
Member since May 2017
Posts: 1,360
|
Post by lookatthat on Aug 21, 2017 11:13:47 GMT -5
I've got pictures of zircon, I now have some on Flickr, but i can't find how to get them here!
|
|
lookatthat
Cave Dweller
Whatever there is to be found.
Member since May 2017
Posts: 1,360
|
Post by lookatthat on Aug 21, 2017 13:38:41 GMT -5
|
|
gemfeller
Cave Dweller
Member since June 2011
Posts: 4,070 
|
Post by gemfeller on Aug 21, 2017 13:49:40 GMT -5
Some varieties of zircon can be heat-treated simply by putting them on the coils of an electric stove element or using a toaster oven. Another method is putting the specimen in a test tube stoppered with cotton and heating it over an alcohol or Bunsen flame. The last method gives better control over color change because it can be observed and quickly removed from the heat when the desired hue is reached.
But not all zircon responds to heat treatment. It's a complicated mineral that's divided into "high" and "low" types depending on its physical properties. Each type has differing hardness, refractive index, density etc. And not all treated colors are stable. Heat-treated "white" zircons tend to turn dark brown after long exposure to UV rays in sunlight.
|
|
lookatthat
Cave Dweller
Whatever there is to be found.
Member since May 2017
Posts: 1,360
|
Post by lookatthat on Aug 22, 2017 8:43:32 GMT -5
Greig, did you see my post with the zircon crystal, didya didya? Just a little bit was peeking out from the matrix when I found it, which was why I think it had been overlooked. It's a good sized one. Also found small pieces of sodalite and some other goodies, but no amazonite. You should definitely check out the pile if you're nearby.
|
|
lookatthat
Cave Dweller
Whatever there is to be found.
Member since May 2017
Posts: 1,360
|
Post by lookatthat on Aug 25, 2017 19:03:14 GMT -5
|
|
lookatthat
Cave Dweller
Whatever there is to be found.
Member since May 2017
Posts: 1,360
|
Post by lookatthat on Aug 25, 2017 19:04:45 GMT -5
Darn it!
|
|
lookatthat
Cave Dweller
Whatever there is to be found.
Member since May 2017
Posts: 1,360
|
Post by lookatthat on Aug 25, 2017 21:28:58 GMT -5
I want actual picture, not link!
|
|
|
|
Post by coloradocliff on Aug 25, 2017 22:23:34 GMT -5
I want actual picture, not link! Click on the picture in rock show that you want to post, then in upper right corner copy onto your mouse clipboard the BB code and paste that into your post. When you post the comment the picture will appear. Eazy peazy Jen, even for another French person like me. lookatthat |
|
lookatthat
Cave Dweller
Whatever there is to be found.
Member since May 2017
Posts: 1,360
|
Post by lookatthat on Aug 26, 2017 8:57:34 GMT -5
Yeah, um right.
How do I copy onto my mouse clipboard the BB code and paste? I don't see anything that says mouse clipboard. Right click, left click, what?
|
|
Maybe you can post some pictures here