Tremolite (probably) in Quartzite and Marble, Bartholomew's Cobble, Sheffield, MA

 Found another cool rock formation.

First hint at visiting this location that something was going on:

 

 Quartzite bedrock!  That is new to me.

 but then i found this nearby:

 

 

Something was afoot!

 

this mess could be found

 

 

the rock could have lots of  textures:

 

tho it could also be nice milky quartz.

 

and then i found these

 

embedded in the bedrock.
 

eventually i found some peices and brought them home for analysis.
here is a handheld chunk with a fibrous mineral.
 

here is a piece of quartz with bladed/fibrous mineral

 

 

at first I was confused when i read that this formation had marble, and there was famous marble quarry with Tremolite mineral in it.  But none of the pieces reacted with my HCl solution.  But finally at home, i ground some of this sugary rock to a powder and tested with HCl.  It bubbled!  Calcite!
 

 

at bottom is a prismatic mineral.  at top is a curious blocky mineral.  not sure if it is related to the bladed, prismatic, fibrous mineral.  it too, is softer than glass.
 
here are some more rosettes of bladed material in sugary marble.

 

 

 

 

 

Then, I found the prize:

Anyway, I suppose this all came from some formation with sandstone and limestone deposits, results of alternating conditions in some shallow sea.  And than at some point in time it got smashed, metamorphosized into quartzite and marble and the tremolite is also a metamorphic product of the calcium in the limestone and the silica in the sandstone.