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Roger Warin
Joined: 23 Jan 2013
Posts: 1232
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 Posted: Dec 26, 2013 04:13 Post subject: 2014 - International year of crystallography: for example, pyrite. |
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2014 marks the centennial of the birth of X-ray crystallography, thanks to the work of William Henry, William Lawrence Bragg (father and son) and Max von Laue (the later was awarded the 1914 Nobel Prize in Physics for his discovery of the diffraction of X-rays by crystals).
2014 will be the International Year of crystallography. This is an opportunity to find specific crystalline forms.
The picture shows an euhedral crystal of pyrite from Elba (Rio Marina). This is a typical habit of Elba.
Roger.
| Description: |
Pyrite
Rio Marina - Elba Island - Italy
2 cm
The cubic form is absent in this crystal. The dominant form is pyritohedron (or pentagonal dodecahedron). But some apexes are truncated by secondary forms, such as the octahedron itself slightly truncated by a diploid (or didodecahedron).
A diploid has 24 faces that are formed from the splitting of the pentagonal faces on the 12 sided pyritohedron. |
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51205 Time(s) |
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| Description: |
Pyrite
Rio Marina - Elba Island - Italy
drawing
Typical habit of Elba pyrite |
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51216 Time(s) |
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| Description: |
Pyrite
Rio Marina - Elba Island - Italy
same specimen
an enlarged apex
{210} pyritohedron
{111} octahedron
{321} diploid |
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51161 Time(s) |
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John S. White
Site Admin
Joined: 04 Sep 2006
Posts: 1298
Location: Stewartstown, Pennsylvania, USA
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| Posted: Dec 26, 2013 06:15 Post subject: Re: 2014 - International year of crystallography : for example, pyrite. |
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| Roger Warin wrote: | Pyrite
same specimen
an enlarged apex
{210} pyritohedron
{111} tetrahedron
{321} diploid |
The triangular face is an octahedron, not a tetrahedron.
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John S. White
aka Rondinaire |
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Roger Warin
Joined: 23 Jan 2013
Posts: 1232
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| Posted: Dec 26, 2013 09:23 Post subject: Re: 2014 - International year of crystallography : for example, pyrite. |
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Many thanks John, forgive me. It is a distraction due to age, I guess.
Roger.
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 5025
Location: Barcelona
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| Posted: Dec 26, 2013 09:29 Post subject: Re: 2014 - International year of crystallography : for example, pyrite. |
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| John S. White wrote: | | The triangular face is an octahedron, not a tetrahedron. |
Fixed
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John S. White
Site Admin
Joined: 04 Sep 2006
Posts: 1298
Location: Stewartstown, Pennsylvania, USA
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| Posted: Dec 26, 2013 10:00 Post subject: Re: 2014 - International year of crystallography : for example, pyrite. |
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Fixed in only one place, it also needs to be fixed in the first caption.
___________________________________
True. Fixed again... ;-)
Jordi
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Rodney B Jackson
Joined: 13 Dec 2013
Posts: 12
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| Posted: Dec 27, 2013 17:27 Post subject: Re: 2014 - International year of crystallography : for example, pyrite. |
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| Naturally formed D&D dice!
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Riccardo Modanesi
Joined: 07 Nov 2011
Posts: 630
Location: Milano
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| Posted: Dec 28, 2013 13:42 Post subject: Re: 2014 - International year of crystallography : for example, pyrite. |
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Hi Roger!
The proper name of the locality is Rio MARINA, not Marino. The specimen is very beautiful, typical of this locality. I found some of these pyrites there.
Greetings from Italy by Riccardo.
| Roger Warin wrote: | 2014 marks the centennial of the birth of X-ray crystallography, thanks to the work of William Henry, William Lawrence Bragg (father and son) and Max von Laue (the later was awarded the 1914 Nobel Prize in Physics for his discovery of the diffraction of X-rays by crystals).
2014 will be the International Year of crystallography. This is an opportunity to find specific crystalline forms.
The picture shows an euhedral crystal of pyrite from Elba (Rio Marino). This is a typical habit of Elba.
Roger. |
_________________
Hi! I'm a collector of minerals since 1973 and a gemmologist. On Summer I always visit mines and quarries all over Europe looking for minerals! Ok, there is time to tell you much much more! Greetings from Italy by Riccardo. |
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Roger Warin
Joined: 23 Jan 2013
Posts: 1232
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| Posted: Dec 28, 2013 15:12 Post subject: Re: 2014 - International year of crystallography : for example, pyrite. |
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Many thanks, Riccardo,
Roger.
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 5025
Location: Barcelona
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| Posted: Jan 06, 2014 13:06 Post subject: Re: 2014 - International year of crystallography |
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| Roger Warin wrote: | 2014 marks the centennial of the birth of X-ray crystallography, thanks to the work of William Henry, William Lawrence Bragg (father and son) and Max von Laue (the later was awarded the 1914 Nobel Prize in Physics for his discovery of the diffraction of X-rays by crystals).
2014 will be the International Year of crystallography. This is an opportunity to find specific crystalline forms.... |
To know more about the International Year of Crystallography please use the IYCR official web page
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John Medici
Joined: 02 Mar 2011
Posts: 124
Location: Ohio
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| Posted: Jan 11, 2014 20:16 Post subject: Re: 2014 - International year of crystallography : for example, pyrite. |
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A couple more pyrites to think about.
| Description: |
Pyrite
Barger Quarry, Lexington, VA, USA
2.5 cm on edge |
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50306 Time(s) |
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Pyrite on quartz
Spruce Claim, King County, WA, USA
3 cm on edge |
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50244 Time(s) |
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field collector |
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Rodney B Jackson
Joined: 13 Dec 2013
Posts: 12
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| Posted: Feb 05, 2014 17:41 Post subject: Re: 2014 - International year of crystallography: for example, pyrite. |
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| Nature is amazing.
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John Medici
Joined: 02 Mar 2011
Posts: 124
Location: Ohio
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| Posted: Feb 28, 2014 15:21 Post subject: Re: 2014 - International year of crystallography: for example, pyrite. |
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For those interested, Chemical and Engineering News (C&EN Vol.92,#7 (2/17/2014) )(Newscripts, last page) lists some postage stamps and crystal growing competitions celebrating IYCR.
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Don Lum
Joined: 03 Sep 2012
Posts: 2900
Location: Arkansas
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| Posted: Feb 28, 2014 17:43 Post subject: Re: 2014 - International year of crystallography: for example, pyrite. |
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| John Medici wrote: | | For those interested, Chemical and Engineering News (C&EN Vol.92,#7 (2/17/2014) )(Newscripts, last page) lists some postage stamps and crystal growing competitions celebrating IYCR. |
Thank you for the information, Dr. Medici.
Don
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bob kerr
Joined: 13 Nov 2011
Posts: 638
Location: Monroeville PA
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| Posted: Feb 28, 2014 18:14 Post subject: Re: 2014 - International year of crystallography: for example, pyrite. |
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has anyone noted the very interesting "pyrite after pyrites" from Racracancha Mine, Peru? they appear to be originally cubic pyrite replaced with another crystal form. how would you experts describe this crystal form?
thanks,
bob kerr
| Description: |
pyrite after cubic pyrite
Racracancha Mine, Tinyahuarco District, Cerro de Pasco Province, Pasco Department, Peru |
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49565 Time(s) |
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Don Lum
Joined: 03 Sep 2012
Posts: 2900
Location: Arkansas
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| Posted: Mar 01, 2014 07:56 Post subject: Re: 2014 - International year of crystallography: for example, pyrite. |
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| bob kerr wrote: | has anyone noted the very interesting "pyrite after pyrites" from Racracancha Mine, Peru? they appear to be originally cubic pyrite replaced with another crystal form. how would you experts describe this crystal form?
thanks,
bob kerr |
Very interesting, Bob. One of the dealers I met in Tucson had some in his room.
Here is his description and I quote:
Pyrite ps. Pyrite
Racracancha Mine, Tinyahuarco Dist., Pasco Prov., Pasco Dept., Peru
A very interesting specimen of pyrite that has pseudomorphed pyrite. I am fairly sure that the numerous small crystals are not epitaxial growths, as fractured surfaces on other pieces show internal voids between the replacement crystals.
Don
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