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Turbo
Joined: 30 Sep 2009
Posts: 260
Location: Delaware
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 Posted: Dec 17, 2009 21:49 Post subject: Blue garnet |
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Today a friend told me about a blue garnet that she had seen on a TV program or something, that was discovered in the ocean somewhere. Does anyone have any information or pictures of this type of garnet? Thanks.
Ed 2
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Jordi Fabre
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parfaitelumiere
Joined: 02 Mar 2008
Posts: 153
Location: Auvergne
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| Posted: Dec 18, 2009 14:36 Post subject: Re: Blue garnet |
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| Hard to find these garnets, and often ugly and little.
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Peter Megaw
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Joined: 13 Jan 2007
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Location: Tucson, Arizona
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| Posted: Dec 18, 2009 15:20 Post subject: Re: Blue garnet |
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There are also irridescent/opaline garnets from near Alamos in southern Sonora. These have a layer of water trapped in the crystal structure, which breaks up the light very much like a fire agate because the garnet is brown. This is a skarn system so they're probably an andradite-grossular composition.
They get to decent size...crystals to 2 cm and 5-10 ct stones are commonly available. I think I have seen that they were for sale on QVC.
There are also some spectacular 'stalactites" of these garnets...but without the fire. It looks like they formed along ribs in the skarn so when broken free they are elongate rods studded with crystal faces...but do have a contact along one side of the rod. Some of these are studded with gemmy transparent perfect dodecahedral crystals 3-4mm across....with a pumpkin orange color...killer micros!
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Turbo
Joined: 30 Sep 2009
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Location: Delaware
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| Posted: Dec 18, 2009 17:52 Post subject: Re: Blue garnet |
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| Hmmmm. None of those really look too much like her description. I've found images of "Bekily color change garnet" on google. They're supposedly from Bekily, Madagascar and can be blue/purple depending on the lighting. I can't find formal mineralogical info or photos of these garnets in the rough. This might be what she was referring to, though.
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robynahawk
Joined: 14 Mar 2008
Posts: 94
Location: Orange County, CA
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| Posted: Dec 18, 2009 18:53 Post subject: Re: Blue garnet |
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| Look for color change or color shift garnet - there is one that goes to a purple - blue!
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robynahawk
Joined: 14 Mar 2008
Posts: 94
Location: Orange County, CA
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| Posted: Dec 18, 2009 18:56 Post subject: Re: Blue garnet |
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| robynahawk wrote: | | Look for color change or color shift garnet - there is one that goes to a purple - blue! |
Yep - that's what I thought - check out Richard Wise's answer here:
https://www.pricescope.com/idealbb/view.asp?topicID=17226
(enlace normalizado por FMF)
He may have photos - he is VERY approachable...
Robyn Hawk
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Granate
Joined: 30 Jul 2009
Posts: 22
Location: Madrid
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| Posted: Dec 19, 2009 09:45 Post subject: Re: Blue garnet |
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| Traditionally said that the garnets are presented in all colors less the blue but as Lapis International in its number 11 devoted to garnet page 4 in 1990s appeared garnets blue in Bekily (Madagascar). However i have not yet seen despite having many garnets in my collection.
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Elise
Joined: 22 Dec 2009
Posts: 243
Location: New York State
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| Posted: Dec 22, 2009 22:53 Post subject: Re: Blue garnet |
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| Turbo wrote: | | They're supposedly from Bekily, Madagascar and can be blue/purple depending on the lighting. I can't find formal mineralogical info or photos of these garnets in the rough. |
I have only seen broken crystals with a few faces intact, but Prof. Henry Hänni has a non-colorchange faceted blue garnet in his collection; a pyrope-spessartine with a distinct vanadium content (V2O3 1.60 wt %) and for which he sent me the following information: calculated end-member mol%: pyrope 39.30%, spessartite 39.50%, almandine 1.40%, uvarovite 1.10%, goldmanite 4.90%, grossular 13.80% (H. Hänni, personal comm, 2008). He also sent a picture a while ago - I am not sure if he would appreciate me uploading it onto forum, but if you Googled blue garnet, you probably ran into the image on one of my chronically unfinished webpages - it is quite blue.
You might also like to read these papers as background: Krzemnicki, M.S., Hänni, H.A. and Reusser, E. (2001) Colour-change garnets from Madagascar: comparison of colorimetric with chemical data. Journal of Gemmology, Vol. 27, 7, pp. 395-408.
Schmetzer, K., and Otteman, J., (1979) Kristallchemie und farbe vandnadium-haltinger granate. Neus Jahrbuch für Mineralogie, Abhandlungen, 136 (2), 147-64.
Best wishes,
Elise
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Turbo
Joined: 30 Sep 2009
Posts: 260
Location: Delaware
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| Posted: Dec 23, 2009 07:58 Post subject: Re: Blue garnet |
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Thanks! This is great!
Ed2
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MGR
Joined: 26 Dec 2009
Posts: 2
Location: Madagascar
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| Posted: Dec 26, 2009 15:15 Post subject: Re: Blue garnet |
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Hello
Pictures of a garnet with a color change from Madagascar.
Gilbert Valero
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Turbo
Joined: 30 Sep 2009
Posts: 260
Location: Delaware
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| Posted: Dec 26, 2009 16:45 Post subject: Re: Blue garnet |
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| MGR wrote: | Hello
Pictures of a garnet with a color change from Madagascar.
Gilbert Valero |
Gilbert, that is a dramatic color shift! Very beautiful in the rough too. Because of all their varieties, I think garnet is one of the most tantalizing gemstones. Thanks for sharing.
Ed 2
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MGR
Joined: 26 Dec 2009
Posts: 2
Location: Madagascar
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| Posted: Dec 27, 2009 00:19 Post subject: Re: Blue garnet |
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Hello
Garnet is the rough that I preferred many
colors
A good IR and affordable.
Here is a
color palette found in the south change color
add a photo of a stone kornérupine unclear
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