Eclogite Facies Garnetite
“Nearly pure garnet from extreme depths”
Garnetite is a rare, spectacular rock composed almost entirely of garnet — typically pyrope-almandine — formed under eclogite facies conditions deep in subduction zones. These nearly monomineralic rocks represent some of the most extreme metamorphic conditions achievable in Earth's crust.
garnet (pyrope-almandine, 80-95%), clinopyroxene (minor), rutile, kyanite, coesite
Western Gneiss Region (Norway), Dabie-Sulu (China), Kokchetav (Kazakhstan), Bohemian Massif (Czech Republic)
7-7.5
Some garnetites from China's Dabie Mountains contain coesite inclusions trapped inside their garnets — microscopic proof that these rocks reached depths exceeding 100 km before their long journey back to the surface.
Test Your Knowledge
What mineral inclusion inside garnetite garnets proves the rock reached depths over 100 km?
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