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Roger Warin
Joined: 23 Jan 2013
Posts: 1177
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Posted: Jul 22, 2018 00:41 Post subject: Re: Sainte Marie-aux-Mines Show 2018 |
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And Paris Museums
Mineral: | Elbaite |
Locality: | Pala District, San Diego County, California, USA | |
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9945 Time(s) |
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Mineral: | Elbaite |
Locality: | Jonas pocket, Itatiaia, Conselheiro Pena, Vale do Rio Doce, Minas Gerais, Brazil | |
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9889 Time(s) |
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Mineral: | Elbaite |
Locality: | Muiâne, Alto Ligonha pegmatite, Zambezia Province, Mozambique | |
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9881 Time(s) |
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Mineral: | Hematite with Orthoclase (variety adularia) |
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9859 Time(s) |
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Mineral: | Orpiment |
Locality: | Jiepaiyu Mine (Shimen Mine), Shimen County, Changde Prefecture, Hunan, China | |
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9945 Time(s) |
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Mineral: | Rhodochrosite |
Locality: | N'Chwaning II Mine, N'Chwaning mining area, Kuruman, Kalahari manganese field (KMF), Northern Cape Province, South Africa | |
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9933 Time(s) |
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Mineral: | Topaz |
Locality: | Virgem da Lapa, Jequitinhonha, Minas Gerais, Brazil | |
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9889 Time(s) |
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Mineral: | Topaz |
Locality: | Murzinka Mine, Sarapulka District, Sverdlovsk Oblast, Ural, Russia | |
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9889 Time(s) |
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Mineral: | Wulfenite |
Locality: | Red Cloud Mine, Trigo Mountains, Silver District, La Paz County, Arizona, USA | |
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9833 Time(s) |
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Roger Warin
Joined: 23 Jan 2013
Posts: 1177
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Posted: Jul 23, 2018 00:46 Post subject: Re: Sainte Marie-aux-Mines Show 2018 |
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The vision of many gold nuggets saturates the eyes. At Sainte Marie, the monotony was broken by associating with the nugget a mineral whose general form was similar. This original idea was realized by the group Mineral & Gem. (MNHN Paris?).
The gold sample is thus highlighted by a remarkable mineral.
Not only are the shapes similar but, for contrast, the colors are complementary. Of course the color of gold is green in transmitted light.
The most breathtaking association is that of gold pseudomorphoses after pyrite compared with malachite on Chessy pyrite.
Octahedron showing a hollow-faced skeletal growth, this type is common to Chessy, and still has a complete pseudomorphose malachite.
In the same way, gold concentrated on the edges of the growing pyrite crystal at Bodaybo (Russia). Alteration dissolves pyrite. It remains the skeletal form where the gold was deposited.
It may be this comparison that gave the idea to the curator to present gold and a mineral.
In 2016, I had already seen several pseudomorphoses of gold after pyrite at Sainte Marie.
Mineral: | Gold |
Locality: | Round Mountain Mine, Round Mountain, Round Mountain District, Nye County, Nevada, USA | |
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with Pyromorphite, Chaillac F. |
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9733 Time(s) |
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Mineral: | Gold |
Locality: | Round Mountain Mine, Round Mountain, Round Mountain District, Nye County, Nevada, USA | |
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With pyromorphite, Les Farges, F. |
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9716 Time(s) |
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Mineral: | Gold |
Locality: | Mato Grosso, Brazil | |
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with Pyromorphite, Les Farges, F. |
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9719 Time(s) |
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Mineral: | Gold |
Locality: | Colorado Quartz Mine, Colorado, Colorado District, Mother Lode Belt, Mariposa County, California, USA | |
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9727 Time(s) |
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Mineral: | Gold |
Locality: | Santa Elena de Uairén, Gran Sabana, Bolívar State, Venezuela | |
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with Bournonite, La Mure, F. |
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9751 Time(s) |
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Mineral: | Gold |
Locality: | Golden Rule Mine, Jumper & Golden Rule Group, Jamestown Mine (Jamestown Group), Jamestown, Jamestown District, Tuolumne County, California, USA | |
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with quartz, La Gardette, F. |
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9737 Time(s) |
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Mineral: | Gold |
Locality: | Round Mountain Mine, Round Mountain, Round Mountain District, Nye County, Nevada, USA | |
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with Sphalerite, dolomite, La Mure, F. |
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9741 Time(s) |
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Mineral: | Gold |
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Bodaybo, Russia Pseudo-or with pseudo-malachite, Chessy, F. |
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9775 Time(s) |
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Mineral: | Gold |
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Bodaybao Russia Seen in 2016 see comment |
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9853 Time(s) |
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Roger Warin
Joined: 23 Jan 2013
Posts: 1177
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Posted: Jul 26, 2018 09:44 Post subject: Re: Sainte Marie-aux-Mines Show 2018 |
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My visit to the Sainte-Marie Show always ends with the visit of Alsatian wine cellars.
This sphere set with corks has a false symmetry, induced by ethyl alcohol.
My reports always end with the smile of this pretty Alsatian carved in the wood and presented on the screw of a press of bunches of grapes.
And finally, a stork on the top of a chapel. Life is sweet in Alsace.
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9571 Time(s) |
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Mineral: | Vigneronne |
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9570 Time(s) |
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Mineral: | Stork |
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9576 Time(s) |
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Gagat Minerals
Joined: 08 Nov 2017
Posts: 43
Location: Greater London
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Posted: Aug 06, 2018 02:37 Post subject: Re: Sainte Marie-aux-Mines Show 2018 |
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Roger Warin wrote: | ... Of course the color of gold is green in transmitted light.
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- I beg your pardon???
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Roger Warin
Joined: 23 Jan 2013
Posts: 1177
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Posted: Aug 06, 2018 07:50 Post subject: Re: Sainte Marie-aux-Mines Show 2018 |
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Hi,
I think you were surprised by what I said. The lure of gold has been the downfall of many people.
Explaining the color of minerals is a difficult task without resorting to difficult theories for the amateur. This is certainly also the case for metals. Why is silver white like polished silver and why is gold yellow and copper red?
It all depends on the efficiency of the absorption of the light beam and its re-emission by reflection. Silver reflects light well according to all the wavelengths that compose it.
If there is an increase in the energy level, the efficiency of absorption decreases, as is the case for gold and copper. The reflectivity is reduced to the blue-green end of the spectrum and the metal appears yellow (gold) or reddish (copper). Gold and copper have low reflectivity at short wavelengths, and are preferentially reflected.
Gold can be beaten into gold leaf less than 100 nm thick, revealing a bluish-green color when light is transmitted through it. Gold is yellow, but not blue-green.
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Gagat Minerals
Joined: 08 Nov 2017
Posts: 43
Location: Greater London
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Posted: Aug 06, 2018 16:34 Post subject: Re: Sainte Marie-aux-Mines Show 2018 |
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Roger Warin wrote: |
Gold can be beaten into gold leaf less than 100 nm thick, revealing a bluish-green color when light is transmitted through it. Gold is yellow, but not blue-green. |
- so please in the future let us know that this is about extremely rare situation (not exactly from this world) because in our reality - gold is ore mineral, not translucent at all (so opaque microscopy is common methode to observe it).
regards
K.Andrzejewski
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