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Roger Warin
Joined: 23 Jan 2013
Posts: 1179
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 Posted: Dec 21, 2013 13:41 Post subject: A bit of heaven |
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Hi,
I wish you a happy Christmas to all.
But I scanned the blue sky and I found this.
What is it?
Roger.
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 4905
Location: Barcelona
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| Posted: Dec 21, 2013 13:49 Post subject: Re: A bit of heaven |
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| Carletonite?
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Roger Warin
Joined: 23 Jan 2013
Posts: 1179
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| Posted: Dec 21, 2013 14:38 Post subject: Re: A bit of heaven |
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Hello,
Trop fort Jordi ! Bravo.
I present to you soon a view of the specimen.
Carletonite
Poudrette Quarry - 1987 collect.
Roger.
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Don Lum
Joined: 03 Sep 2012
Posts: 2869
Location: Arkansas
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| Posted: Dec 21, 2013 14:41 Post subject: Re: A bit of heaven |
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Beautiful specimen, Roger. Thanks for sharing.
Merry Christmas !!!
Don
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Pete Richards
Site Admin
Joined: 29 Dec 2008
Posts: 830
Location: Northeast Ohio
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| Posted: Dec 21, 2013 14:42 Post subject: Re: A bit of heaven |
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That's an incredibly blue carletonite!
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Collecting and studying crystals with interesting habits, twinning, and epitaxy |
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John S. White
Site Admin
Joined: 04 Sep 2006
Posts: 1295
Location: Stewartstown, Pennsylvania, USA
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| Posted: Dec 21, 2013 15:46 Post subject: Re: A bit of heaven |
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Sorry, I can't resist. Jordi pronounces this mineral KAR-LET'-TON-AIT. Took me a while to figure out what he was talking about.
Happy Holidays to All!
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John S. White
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Roger Warin
Joined: 23 Jan 2013
Posts: 1179
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| Posted: Dec 21, 2013 17:18 Post subject: Re: A bit of heaven |
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Hello,
My previous photo (presented as a game) representing the upper part of this crystal of Carletonite from the famous Poudrette Quarry Mont St Hilaire (Quebec).
This crystal collected in 1987 has a good bright color (pic without correction). The central tetragonal prism is intense blue. Growth continued to give a colorless casing. The contrast is striking and net.
During the photo, the colorless portion partially takes the blue hues of the central part. This is typical of the locality.
I do not know the origin of the blue color. But the chromophore group is included in the first stage of crystallization. After, this beautiful impurity disappeared from Carletonite. It is not usual to find anions CO3 in silicates, I think. Is it an alteration process?
Roger.
| Description: |
Carletonite
Poudrette Quarry, Mt St Hilaire, Quebec
1 cm high
collected 1987 |
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Mark Ost
Joined: 18 Mar 2013
Posts: 516
Location: Virginia Beach
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| Posted: Dec 21, 2013 17:32 Post subject: Re: A bit of heaven |
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| My goodness; sky blue for sure!
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Pete Richards
Site Admin
Joined: 29 Dec 2008
Posts: 830
Location: Northeast Ohio
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| Posted: Dec 22, 2013 13:01 Post subject: Re: A bit of heaven |
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| Roger Warin wrote: | (snip)
I do not know the origin of the blue color. But the chromophore group is included in the first stage of crystallization. After, this beautiful impurity disappeared from Carletonite. It is not usual to find anions CO3 in silicates, I think. Is it an alteration process?
Roger. |
Carletonite has a fairly complex composition: KNa4Ca4Si8O18(CO3)4(OH,F) · H2O.
I was unable to find any reference to the cause of the color in carletonite, but it certainly is true that a blue core surrounded by a colorless, white, or even light pink rim is a common pattern. The color zonation is primary - it is not due to alteration.
Mont Saint-Hilaire is an igneous stock intruded into Paleozoic sedimentary rocks including limestones. I believe it also passes through Grenville marble. There were several phases of injection of magmas of somewhat different composition, but basically these are silica-poor syenites. Many blocks of "marble" were pulled into the magma and recrystallized to a coarse texture that is referred to as marble even if the origin may have been limestone. We know that at least some of these xenoliths started out as limestone because fossil brachiopods, now converted to pectolite and aegirine but still recognizable at least to genus, have been found in the quarry. These xenoliths have been extensively modified chemically at their boundaries by interaction with the surrounding rocks.
Carletonite has been found exclusively in these marble xenoliths, typically at their margins where they contact hornfels or igneous breccia. Given this environment, there is plenty of carbonate around to form carbonate minerals, and calcite, dolomite, magnesite, siderite as well as rare-earth carbonates are common in the quarry. So in that regard there is nothing chemically mysterious about finding carletonite also, though Mont Saint-Hilaire is the only know locality for it.
Perhaps surprisingly, carbonates make up 15% of the MSH mineral species list but only 6% of worldwide mineral species as classified according to the Dana system.
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John Medici
Joined: 02 Mar 2011
Posts: 124
Location: Ohio
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| Posted: Dec 23, 2013 21:58 Post subject: Re: A bit of heaven |
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Pretty specimen, Roger, and thanks for the details Pete.
Massive material also has occurred there, but the crystals still win out!
| Description: |
carletonite, etc. sphere
Mont St. Hilaire, Quebec, Canada
3.5 cm diameter
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Rodney B Jackson
Joined: 13 Dec 2013
Posts: 12
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| Posted: Dec 24, 2013 10:51 Post subject: Re: A bit of heaven |
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| Incredible deep colour on these specimens. Lucky dude.
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