pyroxene

Columnar-jointed orendite lamproite lava (Pleistocene, 1.30-1.37 Ma; Black Rock volcanic center, Leucite Hills, Wyoming, USA) 13
by James St. John

Gabbro & diorite & granite dikes (Devonian; Hulls Cove, Mt. Desert Island, Maine, USA) 2
by James St. John

Anorthosite-nelsonite (Poe Mountain Anorthosite, Mesoproterozoic, 1.431-1.436 Ga; Sybille Canyon, Laramie Range, Wyoming, USA) 2
by James St. John

Vesicular basalt (Upper Pleistocene, ~79 ka; lava flow from Amboy Crater, Mojave Desert, California, USA) 1
by James St. John

Bebedourite (Serra Negra-Salitre Complex, Late Cretaceous, 83-84 Ma; NNE of Araxa, Minas Gerais State, Brazil) 3
by James St. John

Mount Scott Volcano (Crater Lake National Park, Oregon, USA) 7
by James St. John

Magnetite-ilmenite (Mesoproterozoic, ~1155 Ma; mine at Tahawus/Sanford Lake, New York State, USA) 1
by James St. John

Peridotite mantle xenoliths in phonotephrite (Peridot Mesa Flow, Middle Pleistocene, 580 ka; Peridot Mesa, San Carlos Volcanic Field, Arizona, USA) 24
by James St. John

Actinolite xenolith in sandorite lamprophyre (Sandor Dike, Neoarchean, 2.703 Ga; Route 17 roadcut northeast of Wasp Lake & north of Wawa, Ontario, Canada) 7
by James St. John

Basalt (Newark Supergroup, Lower Jurassic; Somerset County, New Jersey, USA) 14
by James St. John

Layered gabbros (troctolitic series, Duluth Complex, Mesoproterozoic, 1099 Ma; Thomson Hill Information Center Outcrop, Skyline Parkway, Duluth, Minnesota, USA) 1
by James St. John

Inch-scale layering of plagioclase feldspar and pyroxene (Stillwater Complex, Neoarchean, 2.71 Ga; near the Stillwater Mine, Beartooth Mountains, Montana, USA) 62
by James St. John

Columnar-jointed orendite lamproite lava (Pleistocene, 1.30-1.37 Ma; Black Rock volcanic center, Leucite Hills, Wyoming, USA) 5
by James St. John

Sedimentary xenolith in madupite lamproite (Late Pliocene, 3 Ma; Pilot Butte volcanic center, Leucite Hills, Wyoming, USA) 2
by James St. John

Giants Range Batholith (Neoarchean, 2.674-2.682 Ga; Confusion Hill roadcut, just north of Virginia, Minnesota, USA) 18
by James St. John

Monchiquite lamprophyre dike (Precambrian; Michipicoten River Bridge South roadcut, south of Wawa, Ontario, Canada) 44
by James St. John

Re-exhumed sub-fossil trees (died late 1700s) (Sandy River, Oxbow Park, Oregon, USA) 39
by James St. John

Anorthosite (Ankafotia Anorthosite Massif, Neoproterozoic, ~660 Ma; Madagascar) 16
by James St. John

Wyomingite (Lower Pleistocene, 0.95 Ma; quarry on volcanic cone on Zirkel Mesa, Leucite Hills Volcanic Province, Wyoming, USA) 16
by James St. John

Spinifex komatiite sills in cumulate komatiite lava flow (Upper Komatiitic Unit, Kidd-Munro Assemblage, Neoarchean, 2.711-2.717 Ga; Pyke Hill, near the Potter Mine, east of Timmins, Ontario, Canada) 13
by James St. John

Basalt (Newark Supergroup, Lower Jurassic; Somerset County, New Jersey, USA) 13
by James St. John

Chromite & serpentine (Neoarchean; Red Lodge Chromite District, Beartooth Mountains, Montana, USA) 1
by James St. John

Obsidian & devitrified obsidian gravel (Obsidian Cliff, Yellowstone, Wyoming, USA) 4
by James St. John

Aphyric & partially devitrified rhyolitic obsidian (Roaring Mountain Member, Plateau Rhyolite, Upper Pleistocene, ~59 ka; Obsidian Cliff, Yellowstone, Wyoming, USA) 6
by James St. John

Sedimentary xenolith in madupite lamproite (Late Pliocene, 3 Ma; Pilot Butte volcanic center, Leucite Hills, Wyoming, USA) 1
by James St. John

Wyomingite (Lower Pleistocene, 0.95 Ma; quarry on volcanic cone on Zirkel Mesa, Leucite Hills Volcanic Province, Wyoming, USA) 6
by James St. John

Llao Rock (Crater Lake Caldera, Oregon, USA) 4
by James St. John

Llao Rock (Crater Lake Caldera, Oregon, USA) 9
by James St. John

Anorthosite (Ankafotia Anorthosite Massif, Neoproterozoic, ~660 Ma; Madagascar) 15
by James St. John

Minette dike (Oligocene, 27-32 Ma; Ship Rock's southern dike, Navajo Volcanic Field, New Mexico, USA) 13
by James St. John

Pilot Butte (Pliocene madupite lamproite volcanic center in the Leucite Hills, Wyoming, USA) 19
by James St. John

Columnar-jointed orendite lamproite lava (Pleistocene, 1.30-1.37 Ma; Black Rock volcanic center, Leucite Hills, Wyoming, USA) 3
by James St. John

Columnar-jointed basalt (Lower Eocene, 50-56 Ma; Brown's Hill Quarry, near North Pole, Alaska, USA) 1
by James St. John

Basalt (Newark Supergroup, Lower Jurassic; Somerset County, New Jersey, USA) 5
by James St. John

Reverse fault in inch-scale layered plagioclase feldspar & pyroxene (Stillwater Complex, Neoarchean, 2.71 Ga; near the Stillwater Mine, Beartooth Mountains, Montana, USA) 4
by James St. John

Re-exhumed sub-fossil tree (died late 1700s) (Sandy River, Oxbow Park, Oregon, USA) 14
by James St. John

Actinolite xenolith in sandorite lamprophyre (Sandor Dike, Neoarchean, 2.703 Ga; Route 17 roadcut northeast of Wasp Lake & north of Wawa, Ontario, Canada) 10
by James St. John

Basalt (McCartys Flow, Holocene, ~2.4 to 3.9 ka; southeast of Grants, New Mexico, USA) 9
by James St. John

Anorthosite-nelsonite (Poe Mountain Anorthosite, Mesoproterozoic, 1.431-1.436 Ga; Sybille Canyon, Laramie Range, Wyoming, USA) 1
by James St. John

Aphyric & partially devitrified rhyolitic obsidian (Roaring Mountain Member, Plateau Rhyolite, Upper Pleistocene, ~59 ka; Obsidian Cliff, Yellowstone, Wyoming, USA) 11
by James St. John

Layered gabbros (troctolitic series, Duluth Complex, Mesoproterozoic, 1099 Ma; Thomson Hill Information Center Outcrop, Skyline Parkway, Duluth, Minnesota, USA) 6
by James St. John

Re-exhumed sub-fossil trees (died late 1700s) (Sandy River, Oxbow Park, Oregon, USA) 3
by James St. John

Obsidian & devitrified obsidian gravel (Obsidian Cliff, Yellowstone, Wyoming, USA) 5
by James St. John

Columnar-jointed basalt (Lower Eocene, 50-56 Ma; Brown's Hill Quarry, near North Pole, Alaska, USA) 2
by James St. John

Partially devitrified rhyolitic obsidian (Roaring Mountain Member, Plateau Rhyolite, Upper Pleistocene, ~59 ka; Obsidian Cliff, Yellowstone, Wyoming, USA) 28
by James St. John

Olivine-bearing anthill sediments (Black Rock, Leucite Hills, Wyoming, USA) 5
by James St. John

Basalt (Newark Supergroup, Lower Jurassic; Somerset County, New Jersey, USA) 12
by James St. John

Chromian diopside (Almklovdalen Peridotite, Precambrian; Gusdal Olivine Pit, near Åheim, Norway) 2
by James St. John

Porphyritic shoshonite (Denver Formation, 63-64 Ma, Lower Paleocene; Table Mountain, Golden, Colorado, USA) 3
by James St. John

Madupite lamproite (Late Pliocene, 3 Ma; Pilot Butte volcanic center, Leucite Hills, Wyoming, USA) 6
by James St. John

Basalt (Newark Supergroup, Lower Jurassic; Somerset County, New Jersey, USA) 9
by James St. John

Anorthosite (Lac St. Jean Anorthosite Complex, Mesoproterozoic, 1140-1157 Ma; Lake St-Jean, Quebec, Canada) 4
by James St. John

Aphyric & partially devitrified rhyolitic obsidian (Roaring Mountain Member, Plateau Rhyolite, Upper Pleistocene, ~59 ka; Obsidian Cliff, Yellowstone, Wyoming, USA) 5
by James St. John

Gabbro & diorite & granite dikes (Devonian; Hulls Cove, Mt. Desert Island, Maine, USA) 5
by James St. John

Sedimentary xenolith in madupite lamproite (Late Pliocene, 3 Ma; Pilot Butte volcanic center, Leucite Hills, Wyoming, USA) 3
by James St. John

Columnar-jointed orendite lamproite lava (Pleistocene, 1.30-1.37 Ma; Black Rock volcanic center, Leucite Hills, Wyoming, USA) 1
by James St. John

Anorthosite with labradorite (Wiborg Batholith, 1633 Ma; Kymi Province, Finland) 3
by James St. John

Monchiquite lamprophyre dike (Precambrian; Michipicoten River Bridge South roadcut, south of Wawa, Ontario, Canada) 43
by James St. John

Aphyric & partially devitrified rhyolitic obsidian (Roaring Mountain Member, Plateau Rhyolite, Upper Pleistocene, ~59 ka; Obsidian Cliff, Yellowstone, Wyoming, USA) 9
by James St. John

Magnetite-ilmenite (Mesoproterozoic, ~1155 Ma; mine at Tahawus/Sanford Lake, New York State, USA) 6
by James St. John