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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 1485
Location: Oklahoma
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 Posted: Nov 12, 2018 12:22 Post subject: Re: Collection of Michael Shaw |
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| Mineral: | Muscovite |
| Locality: | | Hiddenite, Alexander County, North Carolina, USA |  |
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| Dimensions: | 1.9 x 2.0 cm |
| Description: |
| A silvery pseudohexagonal muscovite crystal with side illumination showing intense green color due to small amounts of chromium. |
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| Viewed: |
4931 Time(s) |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 870
Location: Paris Area
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| Posted: Nov 12, 2018 13:26 Post subject: Re: Collection of Michael Shaw |
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Nice little specimen Michael!
If am not mistaken, that variety is commonly called fuchsite.
Chrome Muscovite is pretty common in the Colombian emerald belts but I have never seen hexagonal crystals.
Gérard
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 1485
Location: Oklahoma
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| Posted: Nov 12, 2018 15:24 Post subject: Re: Collection of Michael Shaw |
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| Fiebre Verde wrote: | Nice little specimen Michael!
If am not mistaken, that variety is commonly called fuchsite.
Chrome Muscovite is pretty common in the Colombian emerald belts but I have never seen hexagonal crystals.
Gérard |
Thanks Gérard. Yes, fuchsite is the variety of green muscovite resulting from small amounts of chromium substituting for aluminum. Most of the fuchsite I have seen occurs as micaceous masses, but I am aware of at least two other localities that have produced good crystals - Berezovsk, Russia and Malacacheta, Brazil.
Michael
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 1485
Location: Oklahoma
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| Posted: Nov 14, 2018 15:24 Post subject: Re: Collection of Michael Shaw |
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| Mineral: | Quartz (variety amethyst/smoky quartz) |
| Locality: | | Quartz locality, Moosup, Windham County, Connecticut, USA | |
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| Dimensions: | 1.7 x 2.5 cm |
| Description: |
| A doubly-terminated amethyst crystal growing on a zoned crystal of smoky and amethystine quartz |
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| Viewed: |
4835 Time(s) |
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 1485
Location: Oklahoma
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| Posted: Nov 16, 2018 10:14 Post subject: Re: Collection of Michael Shaw |
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I first ran across these interesting Colombian fluorites at the 2016 Tucson show. At that time most of the specimens had a fair amount of damage. I saw a few more pieces this past September at the Denver show. This specimen was collected in 2017 and it is relatively damage-free. In talking with the dealer, who is very familiar with the locality, these fluorites are found in the upper levels of the mine and good specimens are somewhat scarce. Apparently none were found this year. The mid levels of the mine produce some spectacular quartz clusters, and the emeralds are found in the lower mine levels.
| Mineral: | Fluorite |
| Locality: | | Peñas Blancas Mine, Municipio San Pablo de Borbur, Western Emerald Belt, Boyacá Department, Colombia | |
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| Description: |
| Colorless frosted cubic fluorite crystals with prominent green color centers within the corners. As this is an emerald mine, I assume the green color is caused by chromium. 4.6 x 4.8 cm. |
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| Viewed: |
4734 Time(s) |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 870
Location: Paris Area
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| Posted: Nov 16, 2018 11:23 Post subject: Re: Collection of Michael Shaw |
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I have seen many samples of those chromium-rich fluorites - most of them badly damaged - yours is definitely a clean specimen!
Actually beryls and fluorites do mix in Peñas Blancas - two fluorite crystals can be seen in this specimen on the right of the main emerald.
Apologies for the poor quality of the photo.
Gérard
| Mineral: | Beryl (variety emerald), Quartz, Fluorite, Calcite |
| Locality: | | Peñas Blancas Mine, Municipio San Pablo de Borbur, Western Emerald Belt, Boyacá Department, Colombia | |
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| Dimensions: | 10cm across |
| Description: |
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| Viewed: |
4729 Time(s) |
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Firmo Espinar
Joined: 05 Apr 2017
Posts: 431
Location: Medellín, Colombia.
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| Posted: Nov 17, 2018 01:04 Post subject: Re: Collection of Michael Shaw |
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Hi Michael.
Sadly all of these fluorites I´ve seen the last week in Bogotá and also now in Medellín were very damaged. The best specimens fly quickly to USA and Europe, i think. In Madrid 2018 were at least ten nice examples of these fluorites, and also in Expominer Barcelona 2018 we could see same of these green core fluorites.
My Peñas Blancas Mine specialist dealer in Medellín didn´t have any no damage fluorite, and he offers us only really junk in this occasion, pity. And this year the Peñas Blancas Mine quartzs are stretched further than before.
Congratulations Michael. Always you are constantly in touch with the market. And your acquisition is one of the best i´ve ever seen.
From the jungle.
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 1485
Location: Oklahoma
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| Posted: Nov 17, 2018 09:41 Post subject: Re: Collection of Michael Shaw |
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Thank you for your comments Gérard and Franjungle. It's always valuable to hear about what other collectors are finding available at shows and dealers outside the U.S.
Michael
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minsur
Joined: 03 Feb 2015
Posts: 24
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| Posted: Nov 18, 2018 13:25 Post subject: Re: Collection of Michael Shaw |
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Chromium is definitely a valuable option, especially in this part of the world;-)
I was told by my contacts that more probably rare earths, i.e Ytrrium, are responsible for the sometimes really bizarre zonal coloring - might result a bit difficult to really find out.
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 870
Location: Paris Area
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| Posted: Nov 18, 2018 15:01 Post subject: Re: Collection of Michael Shaw |
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| minsur wrote: | Chromium is definitely a valuable option, specially in this part of the world;-)
I was told by my contacts that more probably rare earths, i.e Ytrrium, are responsible for the sometimes really bizarre zonal coloring - might result a bit difficult to really find out. |
Ytrrium is an option.
Various publications also suggest that divalent Samarium (Sm2+) ions can also contribute to the green coloration of the fluorite.
Divalent rare-earth ions at large, contribute to the coloration of hydrothermal fluorite.
As mentioned in Mindat (https://www.mindat.org/min-9889.html) Chrome-Fluorite is a misleading term for this Colombian hydrothermal fluorite.
Gérard
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 1485
Location: Oklahoma
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| Posted: Nov 18, 2018 15:33 Post subject: Re: Collection of Michael Shaw |
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Interesting information to consider. As Minsur suggested, it may be difficult to determine exactly what is responsible for the green zones.
| Mineral: | Brucite |
| Locality: | | Killa Saifullah District, Balochistan (Baluchistan), Pakistan | |
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| Dimensions: | 1.8 x 2.6 cm |
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| Viewed: |
4477 Time(s) |
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 1485
Location: Oklahoma
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| Posted: Nov 21, 2018 08:19 Post subject: Re: Collection of Michael Shaw |
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| Mineral: | Aragonite |
| Locality: | | Salsigne Mine, Salsigne, Mas-Cabardès, Carcassonne, Aude, Occitanie, France | |
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| Dimensions: | 6.7 x 8.6 cm |
| Description: |
| Snow white aragonite helictites collected in the 1980s. |
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| Viewed: |
4379 Time(s) |
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 1485
Location: Oklahoma
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| Posted: Nov 24, 2018 11:05 Post subject: Re: Collection of Michael Shaw |
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| Mineral: | Marcasite, calcite |
| Locality: | | Linwood Mine, Buffalo, Scott County, Iowa, USA | |
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| Dimensions: | 5.1 x 7.2 cm |
| Description: |
| Metallic, brass-yellow spear-shaped marcasite crystals to 2.1 cm on a matrix of colorless calcite crystals. |
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| Viewed: |
4307 Time(s) |
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| Mineral: | Marcasite, calcite |
| Locality: | | Linwood Mine, Buffalo, Scott County, Iowa, USA | |
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| Dimensions: | 5.1 x 7.2 cm |
| Description: |
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| Viewed: |
4305 Time(s) |
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 1485
Location: Oklahoma
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| Posted: Nov 25, 2018 11:09 Post subject: Re: Collection of Michael Shaw |
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A couple of older pieces that I photographed this morning.
| Mineral: | Fluorite |
| Locality: | | Moscona Mine, El Llano, Solís, Corvera de Asturias, Comarca Avilés, Asturias, Principality of Asturias, Spain | |
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| Dimensions: | 5.1 x 7.3 |
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| Viewed: |
4255 Time(s) |
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| Mineral: | Descloizite |
| Locality: | | Berg Aukas, Grootfontein District, Otjozondjupa Region, Namibia | |
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| Dimensions: | 5.7 x 7.8 cm |
| Description: |
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| Viewed: |
4258 Time(s) |
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 1485
Location: Oklahoma
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| Posted: Nov 28, 2018 09:33 Post subject: Re: Collection of Michael Shaw |
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| Mineral: | Barite |
| Locality: | | Indian Head Rock, Basin, Condado Jefferson, Jefferson County, Montana, USA | |
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| Dimensions: | 6.9 x 8.7 cm |
| Description: |
| Blocky amber-colored barite crystals to 1.5 cm with a preferential secondary overgrowth.of creamy white barite. |
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| Viewed: |
4139 Time(s) |
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 1485
Location: Oklahoma
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| Posted: Nov 30, 2018 09:25 Post subject: Re: Collection of Michael Shaw |
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| Mineral: | Fluorite |
| Locality: | | Caaschwitz, Bad Köstritz, Greiz, Thuringia/Thüringen, Germany | |
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| Dimensions: | 2.7 x 2.9 cm |
| Description: |
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| Viewed: |
4065 Time(s) |
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Tobi
Joined: 07 Apr 2009
Posts: 3186
Location: Good Old Germany
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| Posted: Dec 02, 2018 13:55 Post subject: Re: Collection of Michael Shaw |
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| Beautiful Caaschwitz fluorite, Michael!
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 1485
Location: Oklahoma
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| Posted: Dec 02, 2018 15:11 Post subject: Re: Collection of Michael Shaw |
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| Tobi wrote: | | Beautiful Caaschwitz fluorite, Michael! |
Thanks Tobi.
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 1485
Location: Oklahoma
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| Posted: Dec 05, 2018 10:36 Post subject: Re: Collection of Michael Shaw |
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| Mineral: | Arsenopyrite |
| Locality: | | Dalnegorsk, Kavalerovo Mining District, Primorskiy Kray, Far-Eastern Region, Russia | |
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| Dimensions: | 2.2 x 2.1 cm |
| Description: |
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| Viewed: |
3872 Time(s) |
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Michael Shaw
Site Admin
Joined: 30 Apr 2008
Posts: 1485
Location: Oklahoma
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| Posted: Dec 07, 2018 10:10 Post subject: Re: Collection of Michael Shaw |
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| Mineral: | Barite |
| Locality: | | Shirley Basin, Shirley Basin, Medicine Bow, Shirley Basin District, Carbon County, Wyoming, USA | |
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| Dimensions: | 3.0 x 3.8 cm |
| Description: |
| An intergrown group of bladed blue barite crystals to 2.9 cm. from a seldom seen location. |
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| Viewed: |
3807 Time(s) |
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