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A different type of Mexican Geode, please tell me more.
  
  Index -> What is it? - Where is it from?
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Bob Harman




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PostPosted: May 20, 2020 10:44    Post subject: A different type of Mexican Geode, please tell me more.  

Bought at the 2007 Tucson Show is this pictured Mexican geode example plus its other half and several others of the same type. I also obtained the pictured poster with the marketing name of "Rock Candy Crystal Geodes".
Note that my example is the same example as pictured on the poster
These geodes are probably from Chihuahua State, but very different from the common Las Choyas "coconut" geodes and Trancas Estacion Mexican geodes.

These are quartz, var amethyst geodes with many many small, but well formed scepters, reverse scepters and small stellate amethyst crystal groupings.
Also some of the crystals show deep purple amethyst tips and/or bases.
The crystals are well formed and not a druze, as can easily be seen in the poster's inset pix. The groupings, when gently removed from the geode, make for nice small traditional amethyst scepter specimens.

At more recent shows, I have not seen any of this type Mexican geodes for sale.
Can anyone shed more light on this type Mexican geode including whether they continue to be mined. Thanks, Bob



fullsizeoutput_2db0.jpeg
 Mineral: Quartz, var amethyst
 Dimensions: Geode is 8.5cm Amethyst crystals are 3mm - 8mm
 Description:
 Viewed:  438 Time(s)

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 Description:
The 2007 Tucson poster with the geode's marketing name and pictures of the crystals to be found.
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Peter Megaw
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PostPosted: May 20, 2020 10:50    Post subject: Re: A different type of Mexican Geode, please tell me more.  

These look like the geodes from Zacatecas and Aguascalientes...

Need an image of the rind and backside/outside though.

Love the little crystal groups

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Bob Harman




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PostPosted: May 20, 2020 12:44    Post subject: Re: A different type of Mexican Geode, please tell me more.  

Peter, Thanks for your expertise. Here are more pix of the rind and backside of another similar example.
I am most interested in knowing whether hi quality examples of these type geodes are still being mined. Bob



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fullsizeoutput_326a.jpeg
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Peter Megaw
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PostPosted: May 20, 2020 13:38    Post subject: Re: A different type of Mexican Geode, please tell me more.  

This helps...as do matrix shots for other "where is it from" posts

These don't show the ribs that characterize the Zacatecas geodes...not from there

The chloritic rind and quartz style is characteristic of the "other" style of geode from Estacion Trancas in Aldama, Chihuahua. This area produces some very cool chalcedony geodes as well as this style.

The area was quite productive in the late 90s to mid 2000s when the easy surface pickings were exhausted.



20200520_112029.jpg
 Mineral: Geode frontside
 Dimensions: 14 cm
 Description:
backside of a typical Trancas geode...
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20200520_112029.jpg



2014-03-0177.jpg
 Mineral: Opal and chalcedony ps anhydrite
 Dimensions: 14 cm
 Description:
Superb example of the "other" style of Trancas geode. In rare cases in addition to sceptered vapor phase (?) quartz these geodes contain opal and chalcedony pseudomorphs after calcite and both blocky and elongate anhydrite.

Photo by Jeff Scovil...Peter Megaw specimen
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2014-03-0177.jpg



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Bob Harman




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PostPosted: May 20, 2020 15:51    Post subject: Re: A different type of Mexican Geode, please tell me more.  

Thanks Peter!

I find the "more usual" Estacion Trancas geodes also quite fascinating. Very interesting "twisted" quartz formations with fluorescent hyalite opal etc. These formations can also be culled out of the geodes to make very collectible small traditional specimens.

For those interested in reading more about these things, Jeffrey Smith, had an article in R&M vol 85 # 2 on the Mexican geode locality. He and his family visited the site, writing about it. At that time he also was a prolific collector and dealer in these specimens. We knew each other during that time, but I haven't heard of him or his website in recent years. Regards, Bob
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PostPosted: May 20, 2020 16:01    Post subject: Re: A different type of Mexican Geode, please tell me more.  

To be clear...Estacion Trancas is 50 to 60km ESE of LaS Choyas...the classic "coconut" geode locality Jeff wrote about.

I don't think Trancas was really on anyone's radar back then. As I remember I started bringing large volumes of chalcedony geodes from Trancas out in the late 90s ...several tons worth, of which maybe 5% were really interesting.

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