metamorphism

Serpentinite (Paleozoic; Vermont Verde Antique International Quarry, northeast of Rochester, Vermont, USA) 1
by James St. John

Grand Canyon of the Yellowstone River (Yellowstone, Wyoming, USA) 89
by James St. John

Chromite-serpentine rock (Bulqiza Ophiolite; Batra Mine, Dibër County, Albania) 2
by James St. John

Clinker (Wasatch Formation, Lower Eocene; coal fire metamorphism at 19 ka, Late Pleistocene; large block at Interstate 90 west-bound hilltop rest area, east of Buffalo, Powder River Basin, Wyoming, USA) 4
by James St. John

Glaucophane-bearing schist (Attic-Cycladic Crystalline Complex, Cretaceous to Eocene metamorphism, 78 to 42 Ma; Siphnos Island, Aegean Sea) 1
by James St. John

Hard kaolinite (Quaternary; Huntley Kaolinite Mine, Mono County, California, USA) 1
by James St. John

Marinace Green Granite (polymict metaconglomerate) (Ouricuri do Ouro Formation, Mesoproterozoic, ~1.6-1.7 Ga; Bahia, Brazil) 7
by James St. John

Grand Canyon of the Yellowstone River (Yellowstone, Wyoming, USA) 143
by James St. John

Novaculite (metachert) (Arkansas Novaculite, Devonian to Mississippian; Arkansas, USA) 5
by James St. John

Magnetite skarn (Early Miocene, 22-23 Ma; iron mine at Iron Mountain, Utah, USA) 5
by James St. John

Chrysotile (Thetford Mines Ophiolite Complex, Ordovician; Thetford, Quebec, Canada) 3
by James St. John

Anyolite (corundum-amphibole zoisitite) (Neoproterozoic; Mundarara Mine, about 27 km west of Longido, Tanzania) 1
by James St. John

Uvarovite garnets on chromitite (Saranovskiy Massif; Sarany Chromite Mine, Ural Mountains, Russia) 1
by James St. John

Migmatite (Precambrian; near Morrison, Colorado, USA) 1
by James St. John

Glaucophane-bearing schist (Attic-Cycladic Crystalline Complex, Cretaceous to Eocene metamorphism, 78 to 42 Ma; Siphnos Island, Aegean Sea) 4
by James St. John

Amphibolite (Neorchean; Rock Creek Canyon, Beartooth Mountains, Montana, USA) 3
by James St. John

Clinker-bed breccia (Wasatch Formation, Lower Eocene; coal fire metamorphism at 19 ka, Late Pleistocene; large block at Interstate 90 west-bound hilltop rest area, east of Buffalo, Powder River Basin, Wyoming, USA) 8
by James St. John

"Imperial Porphyry" - porphyritic metadacite to porphyritic meta-andesite (Dokhan Volcanics, Neoproterozoic, ~593-602 Ma; Mons Porphyrites, Red Sea Mountains, Egypt) 1
by James St. John

Baked sedimentary xenoliths in clinker (Wasatch Formation, Lower Eocene; coal fire metamorphism at 19 ka, Late Pleistocene; large block at Interstate 90 west-bound hilltop rest area, east of Buffalo, Powder River Basin, Wyoming, USA) 3
by James St. John

Eclogite (Chatanika sequence; north of Fox, Alaska, USA)
by James St. John

Clinker-bed breccia (Wasatch Formation, Lower Eocene; coal fire metamorphism at 19 ka, Late Pleistocene; large block at Interstate 90 west-bound hilltop rest area, east of Buffalo, Powder River Basin, Wyoming, USA) 4
by James St. John

Lineated tourmalinite with argentiferous galena (silver ore) (Umberumberka Lode intruding the Willyama Supergroup, Proterozoic metamorphism, Cambrian vein emplacement; Umberumberka Mine, west of Silverton, Broken Hill Block, New South Wales, Australia) 1
by James St. John

Clinker outcrop (Wasatch Formation, Lower Eocene; coal fire metamorphism at 19 ka, Late Pleistocene; Interstate 90 west-bound hilltop rest area, east of Buffalo, Powder River Basin, Wyoming, USA) 2
by James St. John

Statuarietto White Marble (Apuan Marble Formation, Tertiary metamorphism of Jurassic limestones; Carrara region, Italy) 6
by James St. John

Irish Green Marble (Connemara Marble Formation, Neoproterozoic; Ordovician metamorphism; Galway, Ireland) 4
by James St. John

Garnet schist (Late Cretaceous, 89-90 Ma; Garnet Ledge, about 12 km north of Wrangell, southeastern Alaska, USA) 7
by James St. John

Grand Canyon of the Yellowstone River (Yellowstone, Wyoming, USA) 26
by James St. John

Clinker-bed breccia (Wasatch Formation, Lower Eocene; coal fire metamorphism at 19 ka, Late Pleistocene; large block at Interstate 90 west-bound hilltop rest area, east of Buffalo, Powder River Basin, Wyoming, USA) 9
by James St. John

Uvarovite garnets on chromitite (Saranovskiy Massif; Sarany Chromite Mine, Ural Mountains, Russia) 5
by James St. John

Lamproitic lapilli-ash metatuff (Argyle Lamproite, Mesoproterozoic, 1.178 Ga; Argyle Mine, nw Western Australia)
by James St. John

Chromitite (Neoarchean; North Star Mine, Red Lodge Chromite District, Beartooth Mountains, Montana, USA) 1
by James St. John

Clinker (Wasatch Formation, Lower Eocene; coal fire metamorphism at 19 ka, Late Pleistocene; large block at Interstate 90 west-bound hilltop rest area, east of Buffalo, Powder River Basin, Wyoming, USA) 3
by James St. John

Garnetite (alteration halo around magnetite-rich meta-iron formation) (Archean, metamorphism at ~3.2 Ga & ~2.8 Ga; Quad Creek section - roadcut along the Beartooth Highway, Beartooth Mountains, Montana, USA) 8
by James St. John

Glaucophane-bearing schist (Attic-Cycladic Crystalline Complex, Cretaceous to Eocene metamorphism, 78 to 42 Ma; Siphnos Island, Aegean Sea) 3
by James St. John

Lapis lazuli (lazuritic metamorphite) (Sar-e-Sang Deposit, Sakhi Formation, Precambrian, 2.4-2.7 Ga (?); Sar-e-Sang Mining District, Hindu-Kush Mountains, Afghanistan) 2
by James St. John

Virginia magnitude 2.3 earthquake (10:20 PM, 9 February 2022)
by James St. John

Chromitite (Stillwater Complex, Neoarchean, 2.71 Ga; Beartooth Mountains, Montana, USA) 9
by James St. John

Clinker-bed breccia (Wasatch Formation, Lower Eocene; coal fire metamorphism at 19 ka, Late Pleistocene; large block at Interstate 90 west-bound hilltop rest area, east of Buffalo, Powder River Basin, Wyoming, USA) 3
by James St. John

Phyllite (French Slate, Paleoproterozoic; Snowy Range Road roadcut, Medicine Bow Mountains, Wyoming, USA) 8
by James St. John

Garnet-chlorite schist (Alabama, USA)
by James St. John

View of the Ouachita Mountains Looking East from Hot Springs Mountain Tower, Hot Springs National Park, Arkansas
by Ken Lund

Zinciferous marble fluorescing (Franklin Marble, Mesoproterozoic, 1.03-1.08 Ga; zinc mine in Franklin, northern New Jersey, USA) 7
by James St. John

Anthracite coal (Mammoth Coal, Llewelyn Formation, Middle Pennsylvanian; Pioneer Tunnel Coal Mine, Ashland, Pennsylvania, USA)
by James St. John

Verde Bamboo Granite (epidotic metasandstone) (Ipuçaba Formation, Mesoproterozoic, 1.6-1.7 Ga; Bahia, Brazil) 1
by James St. John

Clinker (Wasatch Formation, Lower Eocene; coal fire metamorphism at 19 ka, Late Pleistocene; large block at Interstate 90 west-bound hilltop rest area, east of Buffalo, Powder River Basin, Wyoming, USA) 2
by James St. John

Pink Diamonds of the Argyle Mine
by James St. John

Lazurite in pyritic marble (Sakhi Formation, Neoarchean; Sar-e-Sang Deposit, Kokcha Valley, Hindu Kush Mountains, Afghanistan)
by James St. John

Eclogite
by James St. John

Staurolite-garnet-mica schist (Mt. Rushmore quadrangle, Black Hills, South Dakota, USA)
by James St. John

Chromitite (Stillwater Complex, Neoarchean, 2.71 Ga; Beartooth Mountains, Montana, USA) 11
by James St. John

Turbidite slates (roadcut between Fox and Livengood, Alaska, USA) 1
by James St. John

Almandine garnet (Madison County, North Carolina, USA) 2
by James St. John

Magnetite banded iron formation (BIF) (Goldman Meadows Formation, Neoarchean, 2.87 Ga; Atlantic City Iron Mine, Wind River Range, Wyoming, USA)
by James St. John

Almandine garnet (Madison County, North Carolina, USA) 1
by James St. John

Cherry blossom stones (pinite) in hornfels (mid-Cretaceous, 98 Ma; Mikata, Honshu Island, Japan) 1
by James St. John

Clinker-bed breccia (Wasatch Formation, Lower Eocene; coal fire metamorphism at 19 ka, Late Pleistocene; large block at Interstate 90 west-bound hilltop rest area, east of Buffalo, Powder River Basin, Wyoming, USA) 1
by James St. John

Clinker-bed breccia (Wasatch Formation, Lower Eocene; coal fire metamorphism at 19 ka, Late Pleistocene; large block at Interstate 90 west-bound hilltop rest area, east of Buffalo, Powder River Basin, Wyoming, USA) 5
by James St. John

View of Ouachita Mountains from Hot Springs Mountain Tower, Hot Springs National Park, Arkansas (Looking North)
by Ken Lund

Geology and Man, Page 7
by darthjenni

Staurolite schist (Keivy Schist; Mt. Ploskaya, Kola Peninsula, Russia) 12
by James St. John