Archean

Russia, Caucasus, Karachay-Cherkess Republic, Dombai. Complex of quartz-biotite, quartz-chlorite gneisses and schists. Archean (?).

Russia, Karachay-Cherkess Republic, Dombai. Complex of quartz-biotite, quartz-chlorite gneisses and schists. Archean (?).

Diamond-Bearing Sopa Conglomerate,Grão Mogol, State of Minas Gerais, Brazil.

Diamond-Bearing Sopa Conglomerate,Diamantina Region, State of Minas Gerais, Brazil.

Russia, Amur Region. Gneiss biotite-amphibole. Diffused interspersed pyrites. Mogochinskaya series. Granulite facies of metamorphism. Consist: amphibole 2-25%, biotite 1-15%, hypersten 0-15%, clinopyroxene 0-5%, plagioclase 20-60%, quartz 15-30%, K-spar 0-53%. Accessory: apatite, zircon, monazite, sphene, rutile, pyrite, magnetite. AR₁^Im