Lineated Schistose Foliation produced by the lining up of elongate amphibole (var. glaucophane) crystals; seen trending lower left and upper right in this image. This is often a Nondescript Rock, easily confused with other rocks, especially amphibolite or various kinds of other Schists. Aside from identifying the specific minerals, the most distinctive feature is the bluish color, although it often verges on black (making it even more confusing with amphibole). The bluish color is not always easy to see, however, especially under fluorsecent lights.
     

The color in this image is exaggerated; in hand specimen it looks much more black, although in the right light the distinct blue color comes through.

 

 

 

 

amphibole -    var. glaucophane Na Plagioclase - Albite Lawsonite - calcium aluminum silicate

 

 

 

amphibolite is associated with major mountain building events when mafic igneous rocks (basalts or gabbros) are metamorphosed through depth of burial, and proximity to batholiths.

 

 

 

Lineated Schistose Foliation produced by the lining up of elongate amphibole (var. glaucophane) crystals; seen trending lower left and upper right in this image.
     

The color of this image is closer to that of the true rock than the whole image.