The Metagranite of Monte Mucrone, eclogitized during the HP alpine metamorphism, preserves magmatic textures and minerals: biotite is surrounded by a garnet corona. Only in decimeter thick shear zones, the metamorphic reaction goes to completion: black patches of biotite have disappeared and the light- green color of jadeite is dominant.
PhotoID292
The Metagranite of Monte Mucrone, eclogitized during the HP alpine metamorphism, preserves magmatic textures and minerals: biotite is surrounded by a garnet corona. Only in decimeter thick shear zones, the metamorphic reaction goes to completion: black patches of biotite have disappeared and the light- green color of jadeite is dominant.
PhotoID292
Photograph: ch.nicollet
Reference: http://christian.nicollet.free.fr/page/Alpes/Mucrone/mucrone.html