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Michael Shaw
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Joined: 30 Apr 2008
Posts: 2252
Location: Oklahoma
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 Posted: Jul 01, 2013 10:24 Post subject: Re: Collection of Michael Shaw |
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More from Peru including my favorite mineral - galena.
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Galena
Pachapaqui District, Bolognesi Province, Ancash Department, Peru
7.4 x 9.4 cm.
Lead gray, cuboctahedral galena crystals associated with pale pink calcite rhombs, cubic pyrite, quartz, and sphalerite. |
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40430 Time(s) |
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Tetrahedrite
Mercedes Mine, Huallanca District, Dos de Mayo Province, Huánuco Department, Peru
5.4 x 7.7 cm
Semi-lustrous, sharply formed tetrahedrite crystals to 2.6 cm. |
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40409 Time(s) |
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Galena
Huanzala Mine, Huallanca District, Dos de Mayo Prov., Hunauco Dept., Peru
5.3 x 8.5 cm.
Galena associated with colorless, bladed Baryte. |
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40411 Time(s) |
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Galena
Alimon Mine, Huayllay District, Pasco Province, Pasco Department, Peru
5.5 x 7.0 cm.
Metallic silver-gray, spinel-twinned galena crystals associated with black sphalerite. |
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40409 Time(s) |
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 2252
Location: Oklahoma
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| Posted: Jul 02, 2013 14:58 Post subject: Re: Collection of Michael Shaw |
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Still more from Peru.
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Siderite
Julcani Mine, Julcani District, Angaraes Province, Huancavelica Department, Peru
3.5 x 7.0 cm.
Brownish, flattened siderite rhombs stacked one on top of another and completely covering matrix. |
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40371 Time(s) |
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Fluorite
Huanzala Mine, Huallanca District, Dos de Mayo Province, Huanuco Dept., Peru
5.5 x 7.0 cm.
Pale green octahedral fluorite crystal measuring 4.0 cm on a matrix of cream to tan dolomite and quartz crystals. |
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40365 Time(s) |
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Alabandite
Uchucchacua Mine, Oyon Province, Lima Dept., Peru
5.1 x 5.6 cm.
Well-formed lustrous black alabandite crystals associated with crystallized pink rhodochrosite. |
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40370 Time(s) |
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Calcite
Morococha District, Yauli Prov., Junin Dept., Peru
4.5 x 6.5 cm.
Sugary-textured, tan scalenohedral calcite crystals, several of which have a secondary growth forming a cap on the original termination. |
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40381 Time(s) |
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Ru Smith
Joined: 13 Oct 2012
Posts: 362
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| Posted: Jul 02, 2013 19:51 Post subject: Re: Collection of Michael Shaw |
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| Very fine specimens and how interesting to have galena as favourite mineral. How did that come about?
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 2252
Location: Oklahoma
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| Posted: Jul 02, 2013 20:46 Post subject: Re: Collection of Michael Shaw |
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| Ru Smith wrote: | | Very fine specimens and how interesting to have galena as favourite mineral. How did that come about? |
Thanks Ru. As for my favorite mineral being galena, one of the first minerals in my collection was a specimen from the Tri-State area of Oklahoma, Kansas, and Missouri. It has a couple of bright cubic galena crystals perched up on a shard of chert. The perfection of those cubes always fascinated me, and the metallic luster was a bonus. I've loved galena ever since.
Michael
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 2252
Location: Oklahoma
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| Posted: Jul 04, 2013 14:58 Post subject: Re: Collection of Michael Shaw |
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Continuing with Peru.
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Baryte
Cerro Warihuyn, Miraflores, Huamalíes Province, Huánuco Department, Peru
3.9 x 6.0 cm.
Transparent, bladed Baryte crystals on pale pinkish-white dolomite. Mined in 2005. |
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40277 Time(s) |
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Quartz
Cantera Quesga, Ancash Department, Peru
4.9 x 8.0 cm.
Colorless transparent quartz crystals scattered over a matrix of platy, mint green fuschite crystals. |
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40282 Time(s) |
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Quartz
Mundo Nuevo Mine, Huamachuco, La Libertad, Peru
3.3 x 4.5 cm.
Doubly terminated Japan law twin associated with small black hübnerite crystals. Collected in 2011. |
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40232 Time(s) |
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 2252
Location: Oklahoma
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| Posted: Jul 06, 2013 13:54 Post subject: Re: Collection of Michael Shaw |
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Today's post will finish Peru. I'll continue to show minerals from South America in my collection in upcoming posts. Up next - Bolivia and Argentina.
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Rhodochrosite
Santa Rita Mine, Morococha District, Yauli Province, Junín Department, Peru
5.0 x 7.0 cm.
A druse of lustrous pink hodochrosite crystals interspersed with transparent quartz crystals on a massive rhodochrosite and sulfide matrix. |
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40163 Time(s) |
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Pyrite
Alimon Mine, Huaron mining district, Huayllay district, Pasco Province, Pasco Department, Peru
8.2 x 10.6 cm.
Typical cubic pyrite crystals with colorless quartz crystals and black sphalerite on a massive sphalerite matrix |
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40182 Time(s) |
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Tetrahedrite
Pachapaqui District, Bolognesi Province, Ancash Department, Peru
5.8 x 8.7 cm.
Metallic black tetrahedrite crystals with manganoan calcite and quartz on a sulfide matrix. |
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40172 Time(s) |
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Rhodochrosite
Uchucchacua Mine, Oyon Province, Lima Dept., Peru
6.8 x 8.7 cm. FOV = 5.0 cm
Gemmy, cherry red rhodochrosite rhombs with stepped faces associated with colorless cuboctahedral fluorite crystals on a black manganese rich matrix. |
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40212 Time(s) |
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 2252
Location: Oklahoma
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| Posted: Jul 08, 2013 11:19 Post subject: Re: Collection of Michael Shaw |
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Collection minerals from Bolivia.
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Copper
Corocoro, Pacajes Province, La Paz Department, Bolivia
2.0 x 3.0 cm.
Sharp pseudomorph of native copper after aragonite. |
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40205 Time(s) |
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Vivianite
Morococala Mine, 280 M Level, Dalence Prov., Oruro Dept., Bolivia
2.5 x 5.0 cm.
Gemmy doubly terminated emerald green vivianite crystals. |
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40355 Time(s) |
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Cassiterite
Viloco Mine, Loayza Province, La Paz Dept., Bolivia
4.5 x 8.2 cm.
Lustrous, dark brown, twinned crystals associated with small quartz crystals. |
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40135 Time(s) |
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Carles Millan
Site Admin
Joined: 05 May 2007
Posts: 1537
Location: Catalonia
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| Posted: Jul 08, 2013 15:49 Post subject: Re: Collection of Michael Shaw |
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| crosstimber wrote: | Copper
Corocoro, Pacajes Province, La Paz Department, Bolivia
2.0 x 3.0 cm.
Sharp pseudomorph of native copper after aragonite. |
Very nice specimen thanks to the uncommon sharp edges, and excellent photo as usual.
Just as a curiosity, I'd like to add that some experts in Bolivian minerals, among them our fellow Alfredo Petrov, believe that it is actually copper after calcite after aragonite. And some specimens with superficial oxidation would contain malachite after copper after calcite after aragonite (needing a very large label).
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 2252
Location: Oklahoma
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| Posted: Jul 08, 2013 21:33 Post subject: Re: Collection of Michael Shaw |
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| Carles Millan wrote: | | crosstimber wrote: | Copper
Corocoro, Pacajes Province, La Paz Department, Bolivia
2.0 x 3.0 cm.
Sharp pseudomorph of native copper after aragonite. |
Very nice specimen thanks to the uncommon sharp edges, and excellent photo as usual.
Just as a curiosity, I'd like to add that some experts in Bolivian minerals, among them our fellow Alfredo Petrov, believe that it is actually copper after calcite after aragonite. And some specimens with superficial oxidation would be malachite after copper after calcite after aragonite (needing a very large label). |
Thanks Carles, that's an interesting observation. I have had an interest in pseudomorphs for about 15 years and pseudomorphs are the focus of one of my sub-collections. While I think they are endlessly fascinating, I also find some of them confusing. Many are pretty straightforward and it is easy to see what the original mineral was. However, when there is a sequence of multiple pseudomorphs it can get pretty tricky.
Michael
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Carles Millan
Site Admin
Joined: 05 May 2007
Posts: 1537
Location: Catalonia
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| Posted: Jul 09, 2013 03:13 Post subject: Re: Collection of Michael Shaw |
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| crosstimber wrote: | | Many (pseudomorphs) are pretty straightforward and it is easy to see what the original mineral was. However, when there is a sequence of multiple pseudomorphs it can get pretty tricky. |
Alfredo told me once that a great deal of copper specimens from that deposit still keep a portion of the original calcium carbonate in the inner part. This material has been analyzed several times and it happens to have calcite crystallographic structure, and not the aragonite's anymore.
Jordi Fabre will forgive me but I'm unable to find that conversation at FMF. If it really exists...
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 5071
Location: Barcelona
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| Posted: Jul 09, 2013 04:14 Post subject: Re: Collection of Michael Shaw |
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| Carles Millan wrote: | | ...Jordi Fabre will forgive me but I'm unable to find that conversation at FMF. If it really exists... |
Here it is: Bolivian copper after aragonite
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Pierre Joubert
Joined: 09 Mar 2012
Posts: 1605
Location: Western Cape
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| Posted: Jul 09, 2013 04:44 Post subject: Re: Collection of Michael Shaw |
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Hi Michael. Beautiful specimens, especially the Rhodochrosites.
_________________
Pierre Joubert
'The tree of silence bears the fruit of peace. ' |
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 2252
Location: Oklahoma
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| Posted: Jul 09, 2013 15:04 Post subject: Re: Collection of Michael Shaw |
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Thanks for your kind comments, Pierre. And thank you to Jordi for supplying the link to the thread on the copper pseudomorphs from Corocoro. I will have to look up Alfredo's article in Rocks and Minerals.
Michael
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Roger Warin
Joined: 23 Jan 2013
Posts: 1240
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| Posted: Jul 09, 2013 15:26 Post subject: Re: Collection of Michael Shaw |
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Amazing pics and specimens.
Roger.
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 2252
Location: Oklahoma
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| Posted: Jul 09, 2013 22:32 Post subject: Re: Collection of Michael Shaw |
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| Roger Warin wrote: | Amazing pics and specimens.
Roger. |
Thank you Roger.
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