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Idahorocks
Joined: 29 Oct 2009
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Location: ID
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Posted: Feb 24, 2010 11:17 Post subject: Citrine from Brazil? |
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Is it true, as I have been hearing. That all Citrine from Brazil is heated Amethyst in order to get the yellow color? And that the only true Citrine, One is able to find, is from the Congo?
Darlene
_________________ “A cultivated woman, wise to know and bold to perform, is the end to which nature works, and the education of the will is the flowering and result of all this geology and astronomy.”
My apologies to Ralph Waldo Emerson |
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Tobi
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Posted: Feb 24, 2010 11:52 Post subject: Re: Citrine from Brazil |
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It is true that the mass material which is sold as citrine from Brazil indeed is heated amethyst. These specimens have a orange or dark-brownish color, while natural citrine is much brighter and has a more pale yellow colour.
This would be a typical "citrine" made of heated amethyst:
https://www.mindat.org/photo-186265.html
while this is a typical sample of natural citrine:
https://www.mindat.org/photo-173523.html
But it is not true that "real" citrines only come from the Congo. There are also good ones (though they are really a rare quartz variety) from Brazil, or also from Russia (e.g. Dal'Negorsk) or other African countries but the Congo.
Cheers!
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John S. White
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Posted: Feb 24, 2010 14:20 Post subject: Re: Citrine from Brazil |
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Natural citrines also come from Charcas, Mexico, I have one. I believe they are also found in Madagascar.
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Jordi Fabre
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Posted: Feb 24, 2010 14:49 Post subject: Re: Citrine from Brazil |
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And in Spain...
Description: |
Citrine Quartz Villasbuenas, Salamanca, Spain Mined in August 2004 Specimen size: 4 × 1.5 × 1.9 cm. Photo: Reference Specimens -> http://www.fabreminerals.com/specimens/RSES-spain-notable-specimens.php#NJ8N1 |
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Amir Akhavan
Joined: 01 Dec 2009
Posts: 95
Location: Hamburg
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Posted: Feb 24, 2010 15:11 Post subject: Re: Citrine from Brazil |
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Great, Jordi, I've heard of Spanish citrines but never saw one. Nice!
More yellow than I thought for sure.
There are many citrine localities.
Good ones come from Norway, for example, deep yellow or yellow green crystals.
Or Urals and far east Siberia.
Brazilian citrine is often honey colored (but that has nothing to do with heated amethyst). The real ones look more like smoky crystals with their color being off.
Transitions to smokey quartz are common (because of the similar color centers).
I'm still not perfectly super-sure that *all* dark yellow Urals crystals are untreated.
_________________ Amir C. Akhavan, Hamburg, Germany |
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Luiz Menezes
Joined: 10 Dec 2009
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Posted: Feb 24, 2010 17:03 Post subject: Re: Citrine from Brazil |
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Brazil s the world largest producer of natural citrines; several tens of pegmatites, mostly in Minas Gerais state, have produced large quantities of large crystals (weighting up to several hundred kilos) with excellent color; among them I can mention the following mines: Morro Redondo (one large quartz pocket found in 1993 produced near 1 ton of high grade citrine, probably the largest and more valuable single find ever in the world), Sapo, Escondido, Pederneiras, Macaco, Pedra Alta, Cruzeiro, Campo Belo (on the 1960's), Aricanga, several mines in Coronel Murta and São Geraldo do Baixio.
The color of natural citrine can never be similar to heat-treated amethyst, the last is orange-yellow, and natural citrine can be light yellow, yellow, brownish-yellow or reddish-yellow (the more appreciated and valuable); unfortunately I don't have photos at the moment.
Luiz Menezes
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Amir Akhavan
Joined: 01 Dec 2009
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Posted: Feb 24, 2010 18:31 Post subject: Re: Citrine from Brazil |
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Hi Luiz,
One of these citrine giants was on display in the (now closed) museum "Steinzeiten" here in Hamburg. It's a 660kg crystal (660kg is twice the size of the biggest Alpine crystals) from the "Pocket de Venancio". There I've seen a documentary about its recovery from the underground pegmatite pocket, very impressive, very hard work. The specimen on display was transparent and honey-colored.
Do you know if the "Pocket de Venancio" is at Morro Redondo?
BTW, a common misconception about citrine is that they all are colored by iron impurities. That is at least not the case for the Brazilian citrines, for example, which are very low in iron. Their color center is related to aluminum impurities and irradiation. The same is probably true for the rare citrines from the Alps and those from Norway, Madagascar, Kazakhstan and the Ural Mountains.
I'm not sure about those from Lueni, Congo, and those from Aldan, Siberia.
Cheers
Amir
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Luiz Menezes
Joined: 10 Dec 2009
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Posted: Feb 24, 2010 22:20 Post subject: Re: Citrine from Brazil |
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Hi Amir:
The huge pocket at Morro Redondo (from where inside a single cavity, that after been dug measured 35 x 10 x 8 m, near 500 tons of quartz were recovered) was called "Carlau's pocket".
I will try to find out where the "Venancio pocket"was found.
Luiz
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José Miguel
Joined: 09 Apr 2007
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Posted: Feb 25, 2010 04:34 Post subject: Re: Citrine from Brazil |
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This a Citrine Quartz from Bresil.
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John S. White
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Posted: Feb 25, 2010 08:43 Post subject: Re: Citrine from Brazil |
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Here is an example of creating citrine by heating amethyst. One half of this geode was not heated, the other was. From Rio Grande do Sul, Brazil.
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Luiz Menezes
Joined: 10 Dec 2009
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Location: Belo Horizonte
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Posted: Feb 25, 2010 10:01 Post subject: Re: Citrine from Brazil |
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Olá José Miguel:
Your nice citrine crystal looks to be from the Itinga ara, on the north of Minas Gerais; if you don't have a more specific info about the locality you can consider my suggestion.
I am annexing here photos of 2 fine citrines from São Geraldo do Baixio, Minas Gerais, from my personnal sollection.
Luiz
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"Cathedral" Citrine - Jaboti mine, São Geraldo do Baixio, MG - 4.7 x 2.2 x 2.0 cm - photo Carlos Menezes |
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Citrine - São Geraldo do Baixio, MG - 4.5 x 3.5 x 2.7 cm - photo Carlos Menezes |
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Idahorocks
Joined: 29 Oct 2009
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Location: ID
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Posted: Feb 25, 2010 12:59 Post subject: Re: Citrine from Brazil |
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All of this is such wonderful information, I shall photograph my selections of Citrine and share with you soon.
Thank you so very much for this opportunity to share.
Darlene
_________________ “A cultivated woman, wise to know and bold to perform, is the end to which nature works, and the education of the will is the flowering and result of all this geology and astronomy.”
My apologies to Ralph Waldo Emerson |
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José Miguel
Joined: 09 Apr 2007
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Posted: Feb 27, 2010 04:30 Post subject: Re: Citrine from Brazil |
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Thank you Luiz, I only have the info of the locality Minas Geraes for my citrine. I will include Itinga.
Now I include a citrine from Urals, Russia.
I have tryed that the color is the most accurate original color.
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Idahorocks
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Posted: Feb 27, 2010 17:29 Post subject: Re: Citrine from Brazil |
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Thank you John S. White that answers my question about this one today.
Darlene
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Heat treated amethyst cluster although sold as citrine cluster |
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_________________ “A cultivated woman, wise to know and bold to perform, is the end to which nature works, and the education of the will is the flowering and result of all this geology and astronomy.”
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Idahorocks
Joined: 29 Oct 2009
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Posted: Feb 27, 2010 17:45 Post subject: Re: Citrine from Brazil |
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Here is one I received from Brazil. It turns out they are real Citrine from what everyone has said here.
Darlene
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_________________ “A cultivated woman, wise to know and bold to perform, is the end to which nature works, and the education of the will is the flowering and result of all this geology and astronomy.”
My apologies to Ralph Waldo Emerson |
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Luiz Menezes
Joined: 10 Dec 2009
Posts: 140
Location: Belo Horizonte
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Posted: Feb 27, 2010 22:09 Post subject: Re: Citrine from Brazil |
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Darlene:
On my opinion the single crystal ("citrine point") shown on the photos is heat treated amethyst, for 2 reasons:
- the color shade tends to orange; heated trated amethyst can be deep orange to light orange, but showing a shade that is not found in natural crystals
- on all photos of natural citrine that were posted in reply of your original question you can see that the crystals have a long prism, showing approximately the same widh from the bottom to the top; your citrine point has a wide top and a narrow bottom, and this shape is typical from amethyst crystals detached from the original geodes, where the most developed faces are the termination faces, followed by much shorter prism faces, and then, on the direction of the bottom, the several crystals packed together interact with each other, resulting on narrower irregular contact surfaces, so that is probably why your polished point has a wider termination and a narrow bottom.
So on my opinion your specimen is a heat treated amethyst that was originally part of a large amethyst geode.
Luiz
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Idahorocks
Joined: 29 Oct 2009
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Posted: Feb 27, 2010 22:57 Post subject: Re: Citrine from Brazil |
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Luiz Menezes
Thank you so very much for pointing this out to me.
Face ters dote com backs you up on this information.
Darlene
_________________ “A cultivated woman, wise to know and bold to perform, is the end to which nature works, and the education of the will is the flowering and result of all this geology and astronomy.”
My apologies to Ralph Waldo Emerson |
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John S. White
Site Admin
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Posted: Feb 28, 2010 06:22 Post subject: Re: Citrine from Brazil |
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I agree with Luiz.
_________________ John S. White
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José Miguel
Joined: 09 Apr 2007
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Posted: Feb 28, 2010 07:01 Post subject: Re: Citrine from Brazil |
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A citrine quartz from China. Shimen, Hunan.
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Citrine quartz. 7,5x5,7x4 cm. |
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José Miguel
Joined: 09 Apr 2007
Posts: 157
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Posted: Feb 28, 2010 07:18 Post subject: Citrine from Zambia |
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Citrine quartz from Kolumo, Zambia.
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Citrine quartz. 11,5x6 cm. |
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