(Massiccio Dora Maira, Cuneo, Piemonte, Italia)
Ref.: Hermann, J. (2003) Experimental evidence for diamond-facies metamorphism in the Dora-Maira massif. Lithos: 70: 163-182.
Very high pressure metamorphism of Mg-rich pelites, at depths over 100km, have created this very unusual pyrope-coesite-quartzite, now exposed in the Western Alps. Famous for its colorless very pure pyrope (over 95% pyrope molecule) as crude crystals up to coconut size. High-pressure phases like ellenbergerite and coesite are preserved only as inclusions in the pyrope, not in the surrounding matrix.
The main composition of the quartzite is : quartz, phengite, talc, kyanite, pyrope.
