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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Jun 11, 2018 01:50 Post subject: Re: Collection of Fiebre Verde - Coscuez (#697) |
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Two generations of calcite, striated tabular form (common) and clear prismatic form (not so common)
Mineral: | Beryl (variety emerald), Calcite |
Locality: | Coscuez mining district, Municipio San Pablo de Borbur, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 40x35x16mm, aggregate=10x15mm |
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25915 Time(s) |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Jun 16, 2018 10:24 Post subject: Re: Collection of Fiebre Verde - Chivor (#692) |
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Group of beryl crystals in a calcite matrix.
Though smaller than the Muzo ones, the Chivor stones often exhibit more sparkle.
Mineral: | Beryl (variety emerald), Calcite, Pyrite |
Locality: | Chivor mining district, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 37x30x32mm, largest xl=10mm |
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25747 Time(s) |
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Mineral: | Beryl (variety emerald), Calcite, Pyrite |
Locality: | Chivor mining district, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 37x30x32mm, largest xl=10mm |
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25743 Time(s) |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Jun 29, 2018 11:47 Post subject: Re: Collection of Fiebre Verde - Chivor (#702) |
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Light-green beryl crystals on a marble-like calcite matrix mixed with patches of black shale.
Mineral: | Beryl (variety emerald), Calcite, Pyrite |
Locality: | Chivor mining district, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 89x138x35mm, 15+ xls up to 10mm |
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25501 Time(s) |
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Mineral: | Beryl (variety emerald), Calcite, Pyrite |
Locality: | Chivor mining district, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 89x138x35mm, 15+ xls up to 10mm |
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25532 Time(s) |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Jul 06, 2018 05:18 Post subject: Re: Collection of Fiebre Verde - Cunas (#699) |
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From Cunas,
Well crystallized dolomite, calcite, clear quartz.
Mineral: | Beryl (variety emerald), Calcite, Dolomite, Quartz |
Locality: | La Pita mining district, Cunas Mine, Municipio Maripí, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 42x24x23mm, xls=8mm |
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25358 Time(s) |
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Mineral: | Beryl (variety emerald), Calcite, Dolomite, Quartz |
Locality: | La Pita mining district, Cunas Mine, Municipio Maripí, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 42x24x23mm, xls=8mm |
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25394 Time(s) |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Jul 09, 2018 13:03 Post subject: Re: Collection of Fiebre Verde - Chivor (#698) |
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Host rock is black shale.
Mineral: | Beryl (variety emerald), Calcite, Pyrite |
Locality: | Chivor mining district, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 39x36x18mm, xl=7mm |
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25205 Time(s) |
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Mineral: | Beryl (variety emerald), Calcite, Pyrite |
Locality: | Chivor mining district, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 39x36x18mm, xl=7mm |
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25252 Time(s) |
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Mineral: | Beryl (variety emerald), Calcite, Pyrite |
Locality: | Chivor mining district, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 39x36x18mm, xl=7mm |
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25243 Time(s) |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Jul 13, 2018 08:10 Post subject: Re: Collection of Fiebre Verde - Coscuez (#694) |
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Coscuez specimen with ~15 thin elongated beryl crystals on a calcite + dolomite matrix.
Mineral: | Beryl (variety emerald), Calcite, Dolomite |
Locality: | Coscuez mining district, Municipio San Pablo de Borbur, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 51x39x33mm, xls up to 12mm |
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25017 Time(s) |
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Mineral: | Beryl (variety emerald), Calcite, Dolomite |
Locality: | Coscuez mining district, Municipio San Pablo de Borbur, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 51x39x33mm, xls up to 12mm |
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25051 Time(s) |
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Pierre Joubert
Joined: 09 Mar 2012
Posts: 1605
Location: Western Cape
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Posted: Jul 13, 2018 09:07 Post subject: Re: Collection of Fiebre Verde |
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I like this last specimen!
_________________ Pierre Joubert
'The tree of silence bears the fruit of peace. ' |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Jul 13, 2018 17:23 Post subject: Re: Collection of Fiebre Verde |
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Pierre Joubert wrote: | I like this last specimen! |
I'm glad you like it Pierre!
Coscuez has a wide variety of crystal forms - elongated prisms are certainly not the most common form.
Gérard
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Jul 17, 2018 06:08 Post subject: Re: Collection of Fiebre Verde - Chivor (#370) |
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Laminar albite, pyrite, dolomite, on black shale.
Mineral: | Beryl (variety emerald), Albite (variety cleavelandite), Dolomite, Pyrite |
Locality: | Chivor mining district, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 40x43x34mm, xl=15mm |
Description: |
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24888 Time(s) |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Jul 22, 2018 08:53 Post subject: Re: Collection of Fiebre Verde - Chivor (#704) |
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Translucent crystal from Palo Arañado.
Weathered pyrite and calcite on black shale.
Mineral: | Beryl (variety emerald), Calcite, Pyrite |
Locality: | Chivor mining district, Palo Arañado Mine, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 51x49x46mm, main xl=20mm |
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24755 Time(s) |
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Mineral: | Beryl (variety emerald), Calcite, Pyrite |
Locality: | Chivor mining district, Palo Arañado Mine, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 51x49x46mm, main xl=20mm |
Description: |
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24737 Time(s) |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Jul 29, 2018 15:48 Post subject: Re: Collection of Fiebre Verde - Chivor (#686) |
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Elongated crystal from Chivor with a complex termination.
Crystal has an unusual hollow cavity down through the upper quarter (5mm).
The void inside the crystal looks like a real crystal - so this is clearly a negative crystal.
The cause of this negative-crystal cavity (crystal-shaped hollow cavity) is unclear to me.
Schmetzer & al. (2011), Chemical and growth zoning in trapiche tourmaline from Zambia – a re-evaluation, JoG, Vol 32, No.5-8
suggest 2 possibilities
1) Trapping of a solid inclusion and subsequent blocking of crystal growth with the formation of a growth induced, elongated void in the direction of crystal growth (arrow) subsequent to trapping of the small mineral grain
2) Trapping of a solid inclusion, movement of the trapped small mineral grain in the direction of the arrow and of the growing crystal face and formation of a growth induced, elongated void in the wake of the moving mineral grain, a mechanism repeated in several steps
Are any of you aware of any other possible explanation?
Mineral: | Beryl (variety emerald) |
Locality: | Chivor mining district, El Oriente Mine, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 20mm |
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Photo taken in daylight conditions |
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24589 Time(s) |
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Mineral: | Beryl (variety emerald) |
Locality: | Chivor mining district, El Oriente Mine, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 20mm |
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24605 Time(s) |
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Mineral: | Beryl (variety emerald) |
Locality: | Chivor mining district, El Oriente Mine, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 20mm |
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24659 Time(s) |
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Mineral: | Beryl (variety emerald) |
Locality: | Chivor mining district, El Oriente Mine, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 20mm |
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24631 Time(s) |
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Roger Warin
Joined: 23 Jan 2013
Posts: 1177
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Posted: Jul 29, 2018 23:59 Post subject: Re: Collection of Fiebre Verde |
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Hi Fiebre Verde,
You said “The cause of this crystal-shaped hollow cavity is unclear to me.”
I think it would be a fluid inclusion, a liquid with maybe even a third gaseous phase (CO2 ?), which has locally prohibited growth (in hydrothermal conditions).
Under these conditions, the crystal grows by forming faces whose indices are consistent with inverted growth.
Subsequently, fluid inclusion escaped.
A solid inclusion would give foreign faces to beryl and would have dropped impurities, I believe.
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Jul 30, 2018 07:34 Post subject: Re: Collection of Fiebre Verde |
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Roger Warin wrote: | Hi Fiebre Verde,
You said “The cause of this crystal-shaped hollow cavity is unclear to me.”
I think it would be a fluid inclusion, a liquid with maybe even a third gaseous phase (CO2 ?), which has locally prohibited growth (in hydrothermal conditions).
Under these conditions, the crystal grows by forming faces whose indices are consistent with inverted growth.
Subsequently, fluid inclusion escaped.
A solid inclusion would give foreign faces to beryl and would have dropped impurities, I believe. |
Hello Roger
I overlooked the geometry aspect of the cavity - faces and overall shape.
I didn't consider the possibility of a trapped fluid inclusion - even less gas inclusion - for being the root cause of the cavity.
Need to become more acquainted with the basic concepts in the physics of crystal growth and the properties of crystal surfaces!
Thanks for your insights Roger.
Gérard
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Roger Warin
Joined: 23 Jan 2013
Posts: 1177
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Posted: Jul 30, 2018 08:50 Post subject: Re: Collection of Fiebre Verde |
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OK, thank you Gerard.
Roger.
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Roger Warin
Joined: 23 Jan 2013
Posts: 1177
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Posted: Jul 30, 2018 22:46 Post subject: Re: Collection of Fiebre Verde |
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Hi Gérard,
Summer nights may be good for insomnia.
Why not think about minerals?
I compared the presence of a cavity in your emerald to the texture of the beryl variety heliodor of Ukraine.
These negative facets are not growth figures, but on the contrary they result from an inverse process, namely dissolution in a hydrothermal medium at the end of growth.
The kinetics of this dissolution depends on the population density of the reticular planes.
These figures are not in relief, but in negative, as in an intaglio. These are hoppers (stairs cavities).
Mineral: | Beryl, var. Heliodor |
Locality: | Khoroshiv (Volodarsk-Volynskii), Zhytomyr Oblast, Ukraine | |
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24441 Time(s) |
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Mineral: | Beryl, var. Heliodor |
Description: |
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24387 Time(s) |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Jul 31, 2018 07:52 Post subject: Re: Collection of Fiebre Verde |
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Roger Warin wrote: | Hi Gérard,
Summer nights may be good for insomnia.
Why not think about minerals?
I compared the presence of a cavity in your emerald to the texture of the beryl variety heliodor of Ukraine.
These negative facets are not growth figures, but on the contrary they result from an inverse process, namely dissolution in a hydrothermal medium at the end of growth.
The kinetics of this dissolution depends on the population density of the reticular planes.
These figures are not in relief, but in negative, as in an intaglio. These are hoppers (stairs cavities). |
Hello Roger,
Thank you for posting this superb example of post-crystallization dissolution!
I know that the quality of the images I posted is not optimal but they all show strong linear features in the c-axis direction in relation with the cavity faces.
Am afraid I don’t have the proper equipment to take close up pictures of these features but I will give it another try.
From what I understand, it’s not always possible to positively attribute patterns and figures to dissolution kinetics or growth kinetics – even less when it’s the result of a combination of both processes. Quite a fascinating topic!
Gérard
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Aug 01, 2018 16:40 Post subject: Re: Collection of Fiebre Verde - Cunas (#695) |
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Beryl prism solidly attached to a calcite crystal.
Dissolution patterns can be seen on all faces.
Mineral: | Beryl (variety emerald), Calcite |
Locality: | La Pita mining district, Cunas Mine, Municipio Maripí, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 33x26x18mm (calcite xl), xls=8.5 & 4mm |
Description: |
The base of the beryl crystal can be seen through the calcite. |
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24328 Time(s) |
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Mineral: | Beryl (variety emerald), Calcite |
Locality: | La Pita mining district, Cunas Mine, Municipio Maripí, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 33x26x18mm (calcite xl), xls=8.5 & 4mm |
Description: |
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24279 Time(s) |
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Mineral: | Beryl (variety emerald), Calcite |
Locality: | La Pita mining district, Cunas Mine, Municipio Maripí, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 33x26x18mm (calcite xl), xls=8.5 & 4mm |
Description: |
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24325 Time(s) |
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Mineral: | Beryl (variety emerald), Calcite |
Locality: | La Pita mining district, Cunas Mine, Municipio Maripí, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 33x26x18mm (calcite xl), xls=8.5 & 4mm |
Description: |
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24321 Time(s) |
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Mineral: | Beryl (variety emerald), Calcite |
Locality: | La Pita mining district, Cunas Mine, Municipio Maripí, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 33x26x18mm (calcite xl), xls=8.5 & 4mm |
Description: |
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24299 Time(s) |
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Mineral: | Beryl (variety emerald), Calcite |
Locality: | La Pita mining district, Cunas Mine, Municipio Maripí, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 33x26x18mm (calcite xl), xls=8.5 & 4mm |
Description: |
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24361 Time(s) |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Aug 19, 2018 16:11 Post subject: Re: Collection of Fiebre Verde - Coscuez (#708) |
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Lustrous dolomite, calcite, pyrite, on black shale.
Mineral: | Beryl (variety emerald), Calcite, Dolomite, Pyrite |
Locality: | Coscuez mining district, Municipio San Pablo de Borbur, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 46x68x26mm, xl=11mm |
Description: |
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24061 Time(s) |
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Mineral: | Beryl (variety emerald), Calcite, Dolomite, Pyrite |
Locality: | Coscuez mining district, Municipio San Pablo de Borbur, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 46x68x26mm, xl=11mm |
Description: |
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24037 Time(s) |
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Mineral: | Beryl (variety emerald), Calcite, Dolomite, Pyrite |
Locality: | Coscuez mining district, Municipio San Pablo de Borbur, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 46x68x26mm, xl=11mm |
Description: |
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24036 Time(s) |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Aug 25, 2018 14:18 Post subject: Re: Collection of Fiebre Verde - Chivor (#706) |
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Semi-transparent double terminated crystal which exhibits many internal cracks and fractures.
Mineral: | Beryl (variety emerald), Calcite, Pyrite |
Locality: | Chivor mining district, Municipio Chivor, Eastern Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 20x20x13mm, xl=20mm |
Description: |
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23919 Time(s) |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Sep 02, 2018 15:17 Post subject: Re: Collection of Fiebre Verde - Coscuez (#654) |
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Aggregate of double terminated crystals.
The white calcite, the clear quartz, the small pyrite nodules, and the crumbly grey shale are all in the back of the aggregate (not seen in the photo).
Mineral: | Beryl (variety emerald), Calcite, Quartz, Pyrite |
Locality: | Coscuez mining district, Municipio San Pablo de Borbur, Western Emerald Belt, Boyacá Department, Colombia | |
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Dimensions: | 39x17x22mm |
Description: |
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23695 Time(s) |
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