[Rockhounds] Garnet & Kyanite

[Lanny]

Hi John and Carolyn

There are a number of areas in the metamorphic complex that Freezeout 
is in that have kyanite and garnet (dominantly almandine). On Moses 
Butte, there is a small zone with kyanite included in garnet. 
Andalusite, kyanite, staurolite and garnet all have been reported on 
the Goat Mountain - Backdome Peak area east of Freezeout. Can't relate 
from experience exactly which ones can be found in the same chunk of 
rock, except the garnet and kyanite together there. It seems that when 
I'm in that area I've got too big of a to do list and thus haven't 
ventured far from the road on that particular ridge.

Mica pseudomorphs after kyanite and staurolite are reported in several 
areas of these metamorphics.

Regards,

Lanny

On Nov 5, 2007, at 5:18 PM, John Siebel wrote:

> Freezeout Mountain, Shoshone County, Idaho sports both kyanite and 
> garnet in mica schist. There is staurolite nearby. Lanny could 
> certainly elaborate on this as his field guides got us up there.
>
> John
>
> ----- Original Message ----- From: "Carolyn Reynard"
> Kyanite forms at a higher pressure and temperature than garnet, so 
> usually they are not together. There are exceptions I have a specimen 
> from Russia that has both. I believe that would indicate my Russian 
> specimen is right on the boundary ( isograd) between the two. 
> (adjacent metamorphic zones on a map are separated by isograds or line 
> of equal grade.)
>
> Not sure about the alteration of kyanite to mica, but I do know 
> cordierite alters to mica, so there is a good possibility. Kyanite is 
> often found  mica schist.
>
> Carolyn Reynard
>
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