Joined: Fri Jun 25, 2010 10:06 pm Posts: 2267 Location: Chapel Hill, NC / Toronto, ON
Over the summer, I cut an extremely dark red zircon. Sure, it looked good, but only in direct summer sunlight at noon in Phoenix. Indoors, it was pitch black. So, thanks to some GREAT information from Lisa, I decided to heat-treat it myself.
A quick 1-second pass with the blowtorch, followed by a 1-minute cooldown, did nothing. This was repeated eight times (for a total of 9x 1-sec passes), with no effect. Lisa had suggested a longer cooldown time, but since this stone was pitch-black I was just messing around anyway.
One of my roommates, a bioengineer with a minor in chem, wanted to know why I was trying to melt gemstones, so I explained heat treatment. He asked if he could experiment a bit, so of course I said yes, and went inside for some water. By the time I got back outside, the concrete was black and the stone was water-white. So much for controlled experimentation...
Post subject: Re: My first home treatment of zircon!
Posted: Tue Jun 26, 2012 6:45 pm
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Joined: Fri Jun 25, 2010 10:06 pm Posts: 2267 Location: Chapel Hill, NC / Toronto, ON
He had the torch on full blast, directly on the stone, the entire time I was getting water. I'm glad I didn't mention the nitrates or permanganates I have on hand, or he probably would have blown up the stone instead...
You might want to keep it in the sunlight for a while and see what happens. I have a handful of Cambodian brown zircon that heat-treat nicely to orange or clear in an alcohol lamp. But some of them will then change and darken in light.
Heat them again and they're nice orange, let them out in sunlight and they get a grey/brown mask. I've got pieces I heated to clear that don't seem to change, so there is a point of no return, at least for my stones.
Thread about the effect is here, though my post images are missing due to a domain name problem with my website (I love technology, especially when you get hacked and then everyone locks you out thinking you're the hacker!) http://gemologyonline.com/Forum/phpBB2/viewtopic.php?f=6&t=9947 And yes, I have to admit that roasting stones over the lamp or with my torch is good fun, no matter what the outcome!
-Allan
_________________ Allan Aoyama http://www.omnifaceter.net <- Omnifaceter is back online!
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