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prcantos
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Joined: 17 Apr 2012
Posts: 243
Location: Granada (Spain)
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 Posted: Aug 27, 2015 16:47 Post subject: Collection of prcantos |
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Hi. I begin this thread here to share my collection with you.
As a collector I am interested in petrogenetic minerals and crystals showing different crystallographic forms or twinning. I prefer crystals in matrix so that I can learn about the geological or petrological environment where they grew. Anyway complex crystals are more easily understood without any matrix.
I think both topics are well exemplified in this specimen: pseudoleucite crystals from Loučná (Czech Republic).
High temperature leucite trapezohedra grew in a phonolite matrix. As temperatura was descending, leucite became a tetragonal mineral, so actual trapezohedra are in fact polysynthetic twins preserving the old isometric form. Subsequently leucite was pseudomorphosed by a mixture of nepheline, orthoclase, and illite (pseudoleucite).
I wish you enjoy my collection.
| Mineral: | pseudoleucite |
| Locality: | | Loucná, Ostrov, Krušné Hory Mountains, Karlovy Vary Region, Bohemia, Czech Republic |  |
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| Dimensions: | 18 x 9 cm. |
| Description: |
| Nepheline + Orthoclase + Illite pseudomorph after Leucite in phonolite matrix. |
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| Viewed: |
10499 Time(s) |
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| Mineral: | pseudoleucite |
| Locality: | | Loucná, Ostrov, Krušné Hory Mountains, Karlovy Vary Region, Bohemia, Czech Republic | |
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| Dimensions: | 3.5 x 3.5 cm. crystal |
| Description: |
| One of the trapezohedral crystals. |
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| Viewed: |
10536 Time(s) |
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| Mineral: | pseudoleucite |
| Locality: | | Loucná, Ostrov, Krušné Hory Mountains, Karlovy Vary Region, Bohemia, Czech Republic | |
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| Dimensions: | FOV 8 cm. |
| Description: |
| Another group of crystals. |
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| Viewed: |
10545 Time(s) |
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_________________
Pablo Rodríguez Cantos
Λίθον˛ον απεδοκίμασαν˛οι οικοδομουντες |
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prcantos
Site Admin
Joined: 17 Apr 2012
Posts: 243
Location: Granada (Spain)
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| Posted: Sep 03, 2015 08:31 Post subject: Re: Collection of prcantos - feldspar |
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A Carlsbad twin of orthoclase in porphyritic granite matrix.
| Mineral: | Orthoclase |
| Locality: | | La Machota Baja outcrop, La Machota Baja, Barrio de la Estación, Zarzalejo, Comarca Sierra Oeste, Community of Madrid, Spain | |
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| Dimensions: | 12 x 6 cm. |
| Description: |
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| Viewed: |
10318 Time(s) |
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| Mineral: | Orthoclase |
| Locality: | | La Machota Baja outcrop, La Machota Baja, Barrio de la Estación, Zarzalejo, Comarca Sierra Oeste, Community of Madrid, Spain | |
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| Dimensions: | 5 x 3.5 cm. |
| Description: |
| The twinned phenocrysts in the same specimen. |
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| Viewed: |
10328 Time(s) |
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_________________
Pablo Rodríguez Cantos
Λίθον˛ον απεδοκίμασαν˛οι οικοδομουντες |
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prcantos
Site Admin
Joined: 17 Apr 2012
Posts: 243
Location: Granada (Spain)
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| Posted: Sep 19, 2015 03:02 Post subject: Re: Collection of prcantos - feldspar |
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Orthoclase and smoky quartz crystals in a graphic pegmatite matrix.
| Mineral: | Orthoclase, Quartz |
| Locality: | | Pegmatites outcrop, Valdemanco, Comarca Sierra de Guadarrama, Community of Madrid, Spain | |
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| Dimensions: | 10 x 8 cm. |
| Description: |
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| Viewed: |
10094 Time(s) |
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| Mineral: | Orthoclase, Quartz |
| Locality: | | Pegmatites outcrop, Valdemanco, Comarca Sierra de Guadarrama, Community of Madrid, Spain | |
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| Dimensions: | FOV 4 cm. |
| Description: |
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| Viewed: |
10079 Time(s) |
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_________________
Pablo Rodríguez Cantos
Λίθον˛ον απεδοκίμασαν˛οι οικοδομουντες |
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