14) High and Ultra-high pressure metamorphism

Nesosilicates

 

 

 

 

pyrope

 

Mg3Al2Si3O12

 

1) eclogites and high pressure mafic and ultramafic rocks

 

olivine, pyroxene, spinel, occasionally diamond

Omphacite is a bright green pyroxene that is commonly found with pyrope in eclogites.

Inosilicates

 

 

 

glaucophane

Na, Mg, Fe2+, Fe3+ clinoamphibole

1) blueschist facies metamorphic rocks

jadeite, lawsonite, aragonite

Riebeckite is a darker and more Fe rich species related to glaucophane, and can be found in certain granites.

Tectosilicates

 

 

Stishovite and coesite high pressure polymorphs of silica; coesite is found in a few high pressure metamorphic environments, in a few xenoliths, and both may be present at sites of meteorite impacts