pyroxene

Triodia sp. (spinifex grass) (Mt. Scott Range, South Australia) 7
by James St. John

Wyomingite (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 45
by James St. John

Chromite bands in serpentinite (Neoarchean; Red Lodge Chromite District, Beartooth Mountains, Montana, USA) 6
by James St. John

Wyomingite (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 53
by James St. John

Matthews Hill (wyomingite lamproite volcanic center in the Leucite Hills, Wyoming, USA) 3
by James St. John

Wyomingitic volcanic breccia (Lower Pleistocene, 2.19-2.56 Ma; Boar's Tusk, Leucite Hills, Wyoming, USA) 3
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) 123
by James St. John

Wyomingitic volcanic breccia with xenoliths (Lower Pleistocene, 2.19-2.56 Ma; Boar's Tusk, Leucite Hills, Wyoming, USA) 3
by James St. John

Metabentonite in silicate-rich marble (Gouverneur Marble, Mesoproterozoic, ~1.1 Ga; Route 11 roadcut southwest of Canton, New York State, USA) 41
by James St. John

Actinolite xenolith (Sandor Dike, Neoarchean, 2.703 Ga; Route 17 roadcut northeast of Wasp Lake & north of Wawa, Ontario, Canada) 6
by James St. John

Triodia sp. (spinifex grass) (Mt. Scott Range, South Australia) 2
by James St. John

Wyomingite with xenolith (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 8
by James St. John

Wyomingite (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 28
by James St. John

Wyomingite (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 43
by James St. John

Black Rock (Pleistocene olivine orendite lamproite volcanic center in the Leucite Hills, Wyoming, USA) 21
by James St. John

Stillwater Complex (Neoarchean, 2.71 Ga; near the Stillwater Mine, Beartooth Mountains, Montana, USA) 36
by James St. John

Boar's Tusk (Early Pleistocene wyomingite volcanic center in the Leucite Hills, Wyoming, USA) 48
by James St. John

Stillwater Complex (Neoarchean, 2.71 Ga; near the Stillwater Mine, Beartooth Mountains, Montana, USA) 35
by James St. John

Metakomatiites (Upper Komatiitic Unit, Kidd-Munro Assemblage, Neoarchean, 2.711-2.719 Ga; Pyke Hill, near the Potter Mine, east of Timmins, Ontario, Canada) 1
by James St. John

Matthews Hill (wyomingite lamproite volcanic center in the Leucite Hills, Wyoming, USA) 8
by James St. John

Wyomingite (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 46
by James St. John

Wyomingitic volcanic breccia (Lower Pleistocene, 2.19-2.56 Ma; Boar's Tusk, Leucite Hills, Wyoming, USA) 2
by James St. John

Boar's Tusk (Early Pleistocene wyomingite volcanic center in the Leucite Hills, Wyoming, USA) 12
by James St. John

Llao Rock (Crater Lake Caldera, Oregon, USA) 18
by James St. John

Wyomingitic volcanic breccia (Lower Pleistocene, 2.19-2.56 Ma; Boar's Tusk, Leucite Hills, Wyoming, USA) 9
by James St. John

Wyomingite (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 50
by James St. John

Matthews Hill (wyomingite lamproite volcanic center in the Leucite Hills, Wyoming, 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) 122
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) 126
by James St. John

Rainbow obsidian (Jalisco State, Mexico) 28
by James St. John

Wyomingite (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 51
by James St. John

Boar's Tusk (Early Pleistocene wyomingite volcanic center in the Leucite Hills, Wyoming, USA) 16
by James St. John

Boar's Tusk (Early Pleistocene wyomingite volcanic center in the Leucite Hills, Wyoming, USA) 14
by James St. John

Wyomingitic volcanic breccia (Lower Pleistocene, 2.19-2.56 Ma; Boar's Tusk, Leucite Hills, Wyoming, USA) 37
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) 124
by James St. John

Wyomingite (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 47
by James St. John

Wyomingite (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 54
by James St. John

Rainbow obsidian (Jalisco State, Mexico) 12
by James St. John

Wyomingitic volcanic breccia with xenoliths (Lower Pleistocene, 2.19-2.56 Ma; Boar's Tusk, Leucite Hills, Wyoming, USA) 2
by James St. John

Boar's Tusk (Early Pleistocene wyomingite volcanic center in the Leucite Hills, Wyoming, USA) 50
by James St. John

Wyomingite (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 35
by James St. John

Stillwater Complex (Neoarchean, 2.71 Ga; near the Stillwater Mine, Beartooth Mountains, Montana, USA) 7
by James St. John

Wyomingitic volcanic breccia (Lower Pleistocene, 2.19-2.56 Ma; Boar's Tusk, Leucite Hills, Wyoming, USA) 6
by James St. John

Wyomingitic volcanic breccia (Lower Pleistocene, 2.19-2.56 Ma; Boar's Tusk, Leucite Hills, Wyoming, USA) 12
by James St. John

Boar's Tusk (Early Pleistocene wyomingite volcanic center in the Leucite Hills, Wyoming, USA) 2
by James St. John

Wyomingite (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 1
by James St. John

Chromite band in serpentinite (Neoarchean; Red Lodge Chromite District, Beartooth Mountains, Montana, USA) 3
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) 111
by James St. John

Stillwater Complex (Neoarchean, 2.71 Ga; near the Stillwater Mine, Beartooth Mountains, Montana, USA) 8
by James St. John

Dune slip face (Oregon Dunes, Florence, Oregon, USA) 5
by James St. John

Wyomingite (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 27
by James St. John

Wyomingitic volcanic breccia (Lower Pleistocene, 2.19-2.56 Ma; Boar's Tusk, Leucite Hills, Wyoming, USA) 36
by James St. John

Boar's Tusk (Early Pleistocene wyomingite volcanic center in the Leucite Hills, Wyoming, USA) 13
by James St. John

Spinifex komatiite sill 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) 39
by James St. John

Spinifex komatiite sill 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) 33
by James St. John

Boar's Tusk (Early Pleistocene wyomingite volcanic center in the Leucite Hills, Wyoming, USA) 15
by James St. John

Metabentonite in silicate-rich marble (Gouverneur Marble, Mesoproterozoic, ~1.1 Ga; Route 11 roadcut southwest of Canton, New York State, USA) 29
by James St. John

Wyomingite (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 48
by James St. John

Chromite band in serpentinite (Neoarchean; Red Lodge Chromite District, Beartooth Mountains, Montana, USA) 2
by James St. John

Wyomingite (Pleistocene, 950-960 ka; Zirkel Mesa, Leucite Hills, Wyoming, USA) 42
by James St. John