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Eduardoo
Joined: 01 Jun 2010
Posts: 72
Location: Quito
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Posted: Jun 26, 2010 23:25 Post subject: How is this green quartz produced? |
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I bought this crystal that was being offered as bolivianite (ametrine) really cheap. I knew it could not be ametrine because of the notorious green color.
Now, as far as I can tell, the thing is indeed quartz (SG and hardness match). Of course I could be wrong.
How is this green quartz produced?
Regards.
Eduardo
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 4905
Location: Barcelona
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Posted: Aug 01, 2010 02:07 Post subject: Re: How is this green quartz produced? |
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Eduardoo wrote: | I knew it could not be ametrine because of the notorious green color...
...How is this green quartz produced? |
You can find a lot of info in this previous discussion: "Quartz variety: Prase" -> https://www.mineral-forum.com/message-board/viewtopic.php?t=813
BTW, I can't see the "notorious green" color in the photo; maybe you can try to publish a new photo...?
Jordi
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Eduardoo
Joined: 01 Jun 2010
Posts: 72
Location: Quito
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Posted: Aug 01, 2010 10:18 Post subject: Re: How is this green quartz produced? |
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Hi Jordi:
Here is a better photo. (BTW it would be great if the professional who takes the photos for your site gives us some practical tips about lightning)
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Fake ametrine?. Yellow, green and some purple. |
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Real ametrine? Light yellow and purple. It came from the same source as the fake one, so maybe this is also a fake. |
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 4905
Location: Barcelona
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Posted: Aug 01, 2010 10:33 Post subject: Re: How is this green quartz produced? |
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Eduardoo wrote: | ...BTW it would be great if the professional who takes the photos for your site gives us some practical tips about lightning |
Have you seen this? -> https://www.mineral-forum.com/message-board/viewtopic.php?p=12498 , quite good....
About the natural or fake "ametrines", both specimens looks more or less natural to me. The real question is if "ametrine" is a defining term or just a commercial name invented to sell better rocks and consequently imprecise (as is totally subjective try to define if a rock is enough green, purple, yellow or somewhat)
We try to use just IMA names ( https://pubsites.uws.edu.au/ima-cnmnc/MINERALlist.pdf ) , more precise I believe...
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Peter Megaw
Site Admin
Joined: 13 Jan 2007
Posts: 963
Location: Tucson, Arizona
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Posted: Aug 01, 2010 11:45 Post subject: Re: How is this green quartz produced? |
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Ametrine is definitely a colloquial "rock-hound" name, but is quite descriptive of the phenomenon of crystals showing adjoining zones of amethyst and citrine color (also colloquial terms, but of great antiquity). Some of the crystals I have seen of this are quite remarkable and the stones cut from it can be strikingly bicolored.
Might be worth noting that both of the stones shown here are faceted gems, and neither are "crystals".
I have not seen any uncut crystals with green zones, but one could theorize that if the amethyst purple is due to iron, that if some crystals grew under more reducing conditions, the iron might impart a green color...and the green here does look like a reduced iron green to me.
Anyone seen any work on attempts to synthesize ametrine? Both amethyst and citrine can be readily synthesized, so perhaps ametrine can be as well...and perhaps the green shown here reflects a contaminated batch or failed attempt on the amethyst stage.
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Tenney Naumer
Joined: 12 Apr 2010
Posts: 10
Location: Marion, Illinois
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Posted: Aug 01, 2010 13:46 Post subject: Re: How is this green quartz produced? |
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Down here in Brazil we have a site similar to eBay called MercadoLivre (ML).
ML is chock full of synthetic quartzes of all variations of bicolors, including purple and yellow, blue and green, purple and clear, green and yellow, orange and blue, you get the picture. They are all hydrothermal quartzes being sold as 100% natural, of course.
This has been going on for at least 4 years, maybe more.
These stones can also be purchased on eBay.
_________________ Blog: "Gemstone News and Local Color from Teófilo Otoni" |
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