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 Post subject: Seperating Tsavorite,Mali ,Grossular-Andradite Mix Garnets
PostPosted: Wed Feb 28, 2018 3:16 pm 
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Tsavorite can be mis-identified. Could be a green chromium bearing Mali Garnet too. A Grossular-Andradite Mix. Normally higher RI but not impossible

Check Kirk Feral Homepage...very helpful!

https://www.gemstonemagnetism.com/under ... etism.html

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 Post subject: Re: Post subject: Seperating Tsavorite,Mali ,Grossular-Andra
PostPosted: Wed Feb 28, 2018 3:44 pm 
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Would some andradite content disqualify a stone from being called a tsavorite if it is in the right color range? Assuming Cr grossular qualifies, though I am not sure how debated that is.


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 Post subject: Re Post subject: Seperating Tsavorite,Mali ,Grossular-Andrad
PostPosted: Wed Feb 28, 2018 5:43 pm 
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Difficult....

garnets :roll:

To my knowledge mali garnet have sometimes a fine green or colorless core with low iron content - and lower RI. And they are rare! Chromian grossular...chromian Mali, chromian Grandite....

Tsavorite - no.

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 Post subject: Re: Post subject: Seperating Tsavorite,Mali ,Grossular-Andra
PostPosted: Wed Feb 28, 2018 5:57 pm 
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Removing a couple variables, how do you feel about the name being applied to, say, the Canadian chrome grossulars that are of essentially equal color quality to a V-colored tsavorite?


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 Post subject: Re: Post subject: Seperating Tsavorite,Mali ,Grossular-Andra
PostPosted: Thu Mar 01, 2018 1:50 am 
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In my collection it would be labeled as "Cr-Grossular, Quebec, Kanada".

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 Post subject: Re: Post subject: Seperating Tsavorite,Mali ,Grossular-Andra
PostPosted: Thu Mar 01, 2018 5:26 pm 
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I did as I said and started a new thread.
Although all this information is really fascinating (I'm serious, it IS!) we have no additional information from Ross. We don't even know what the mystery stone looks like.
No additional inclusion pics.
No pic of the actual stone.
Maybe all the posts (with the exception of the first couple) should be moved to a thread called Green Chrome Grossulars and their Varieties


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 Post subject: Re: Post subject: Seperating Tsavorite,Mali ,Grossular-Andra
PostPosted: Thu Mar 01, 2018 5:35 pm 
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Yeah, I was just trying to get some juice out of the thread while we wait. It's an interesting topic, and while I'm sure emotions about the definition run high in some circles I haven't seen any fighting or name-calling like I have over, say, what qualifies as imperial topaz.


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 Post subject: Re: Post subject: Seperating Tsavorite,Mali ,Grossular-Andra
PostPosted: Thu Mar 01, 2018 6:17 pm 
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Total success Stephen. Too interesting not to have its own platform!
I'm going to make a new thread. Let's add some pictures and other points of interest on chrome grossular.

PS The color of precious topaz is an opinion, like padpradscha and with some (cough cough) alexandrite.


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 Post subject: Re: Seperating Tsavorite,Mali ,Grossular-Andradite Mix Garne
PostPosted: Thu Mar 01, 2018 6:32 pm 
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OK!

So some work the next days... :D

By the way...

Here is a canadium chromian grossular offered

http://auction3.mineral-auctions.com/it ... emID=26385

Grossular....yes

green....yes

chromian.... yes ( I believe the vendor :D )

Tsavorite....No not in my opinion...

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 Post subject: Re: Seperating Tsavorite,Mali ,Grossular-Andradite Mix Garne
PostPosted: Thu Mar 01, 2018 6:37 pm 
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Let's start with a a great article from Dick Hughes.
http://www.ruby-sapphire.com/tsavorite- ... beauty.htm

Marlow, has tsavorite been found elsewhere other than East Africa?


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 Post subject: Re: Seperating Tsavorite,Mali ,Grossular-Andradite Mix Garne
PostPosted: Thu Mar 01, 2018 7:56 pm 
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The posted example of chrome grossular doesn't have sufficient color quality either way.
But can you tell me just by looking which of these is chrome grossular and which is vanadian grossular? Certainly not from quality of color.
Image
Image

In addition to the madagascar deposit mentioned in the article and the tiny canadian production bits of grossular in the same color range come out of Afghanistan from time to time, but I don't know what the colorants have proven to be. They don't seem to have been enough to significantly affect the market but they may find more one day.

Personally I think this situation is reasonably analogous to emerald and the various debates over Cr/V. In the end I think trying to divide emerald from vanadian green beryl was regrettable, and it would be better to not make the same mistake again. I guess my stance would generally be that gem varietal names should be defined based on basic gemological properties (ie, species, color, phenomena, etc).

I've conveniently left "basic gemological properties" without a specific definition, since these vague principles run into difficulty when you get into the intricacies of, say, paraiba tourmaline, but at least the chromophore there is (per proponents) tied to a color quality unattainable with other chromophores. And they don't help that much with how to deal with cases like 'grandite', since its SG/RI are distinct from either endmember. But generally speaking, if it has sufficiently fine green color and it's majority grossular then I'd probably want to call it tsavorite. The amount of Mali garnet that would qualify would be so minor it wouldn't matter much either way anyway.

Of course for future predictions the one that's on the horizon right now is probably the Ethiopian green grossular (picture from Tucson last year, saw the similar but larger parcels this year).
Image
For now it's small material with a very heft pricetag (400/g!!!) that nobody seems interested in paying. But if production increases there will likely be at least some pressure in the market to sell it as tsavorite (by which I mean it's already being sold as tsavorite, but nobody cares yet). I think we'll agree that the pictured stones don't match either of our definitions. On the other hand 'grossular' doesn't have the best ring, so something will probably have to be done there.


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 Post subject: Re: Seperating Tsavorite,Mali ,Grossular-Andradite Mix Garne
PostPosted: Fri Mar 02, 2018 3:49 am 
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I agree 100 % !

The first crystal mix in a parcel of tsavorites from Kenia/Tanzanis - no doubt from this color tsavorite would be ok.

I am a bit careful judging from pics - really difficult to get rhe right color.

I have to tiny afghan "Tsavorites" and a parcel bought from GSK from Jeffreys Mine Canada - try to make pic. The canadian stones are soooo close and quite large so I don't whether rhey are really from Canada....

But some show pink fluorescence (LW). Only a small amount of eastafrican Tsavo show fluorescence ( low iron and enough chromium).

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