[Rockhounds] Blue Schist

[Pmodreski at aol.com]

Hi Larry,
 
I'll give an answer.  Blueschist (it's usually written as one word)  actually 
refers to a particular kind of metamorphic rock, glaucophane  schist.  This 
contains the mineral glaucophane, which is actually kind of a  bluish-purple. 
It's found in areas such as coastal northern California--the  Franciscan 
Formation.  Someone who lives in the S.F. Bay area and  knows about local geologic 
sites would probably know how to obtain a  specimen.  
 
It's not really noted for good crystals, just a somewhat unusual  
grayish-bluish-purplish rock that is of interest to geologists.   Glaucophane schist 
occurs in metamorphic rocks that form in a somewhat unusual  environment of high 
pressures and relatively low temperatures; in zones of plate  collision and 
subduction (e.g., California!).
 
Pete Modreski
 
 
 
In a message dated 7/17/2007 8:06:19 AM Mountain Daylight Time,  
larryrush at worldnet.att.net writes:

List: I  received this from a student in Fla. I don't know of any "blue 
schist", the  only thing that comes to mind is possibly a finely divided kyanite 
schist. Can  anyone help her?

Larry Rush







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