James St. John:
Rhyolitic perlite (Yellowstone, Wyoming, USA)
James St. John:
Hot Creek Rhyolite Flow (Pleistocene, 288 or 333 ka; Hot Creek Gorge, Long Valley Caldera, California, USA) 19
James St. John:
Hot Creek Rhyolite Flow (Pleistocene, 288 or 333 ka; Hot Creek Gorge, Long Valley Caldera, California, USA) 20
James St. John:
Hot Creek Rhyolite Flow (Pleistocene, 288 or 333 ka; Hot Creek Gorge, Long Valley Caldera, California, USA) 21
James St. John:
Hot Creek Rhyolite Flow (Pleistocene, 288 or 333 ka; Hot Creek Gorge, Long Valley Caldera, California, USA) 22
James St. John:
Hot Creek Rhyolite Flow (Pleistocene, 288 or 333 ka; Hot Creek Gorge, Long Valley Caldera, California, USA) 27
James St. John:
Hot Creek Rhyolite Flow (Pleistocene, 288 or 333 ka; Hot Creek Gorge, Long Valley Caldera, California, USA) 28
James St. John:
Hot Creek Rhyolite Flow (Pleistocene, 288 or 333 ka; Hot Creek Gorge, Long Valley Caldera, California, USA) 37
James St. John:
Hot Creek Rhyolite Flow (Pleistocene, 288 or 333 ka; Hot Creek Gorge, Long Valley Caldera, California, USA) 38
James St. John:
Hot Creek Rhyolite Flow (Pleistocene, 288 or 333 ka; Hot Creek Gorge, Long Valley Caldera, California, USA) 39
James St. John:
Hot Creek Rhyolite Flow (Pleistocene, 288 or 333 ka; Hot Creek Gorge, Long Valley Caldera, California, USA) 40
James St. John:
Hot Creek Rhyolite Flow (Pleistocene, 288 or 333 ka; Hot Creek Gorge, Long Valley Caldera, California, USA) 41
James St. John:
Hot Creek Rhyolite Flow (Pleistocene, 288 or 333 ka; Hot Creek Gorge, Long Valley Caldera, California, USA) 42
James St. John:
Hot Creek Rhyolite Flow (Pleistocene, 288 or 333 ka; Hot Creek Gorge, Long Valley Caldera, California, USA) 43
James St. John:
Obsidian in perlite (Arnett Rhyolite, Miocene, ~15-18.6 Ma; near Superior, Arizona, USA) 1
James St. John:
Obsidian in perlite (Arnett Rhyolite, Miocene, ~15-18.6 Ma; near Superior, Arizona, USA) 2
James St. John:
Perlite (Arnett Rhyolite, Miocene, ~15-18.6 Ma; near Superior, Arizona, USA) 1
James St. John:
Perlite (Arnett Rhyolite, Miocene, ~15-18.6 Ma; near Superior, Arizona, USA) 2
James St. John:
Perlite (Arnett Rhyolite, Miocene, ~15-18.6 Ma; near Superior, Arizona, USA) 3
James St. John:
Perlite (Arnett Rhyolite, Miocene, ~15-18.6 Ma; near Superior, Arizona, USA) 4
James St. John:
Perlite (Arnett Rhyolite, Miocene, ~15-18.6 Ma; near Superior, Arizona, USA) 5
James St. John:
Perlite (Hollinger Quarry, Wilson Creek Range, Nevada, USA) 1
James St. John:
Perlite (Hollinger Quarry, Wilson Creek Range, Nevada, USA) 2
James St. John:
Perlite (Hollinger Quarry, Wilson Creek Range, Nevada, USA) 3
James St. John:
Perlite (Hollinger Quarry, Wilson Creek Range, Nevada, USA) 4
James St. John:
Perlite (Hollinger Quarry, Wilson Creek Range, Nevada, USA) 5
James St. John:
Perlite (Hollinger Quarry, Wilson Creek Range, Nevada, USA) 6
James St. John:
Perlite (Fish Springs Perlite Deposit, Pleistocene; American Perlite Mine, Inyo County, California, USA) 1
James St. John:
Perlite (Fish Springs Perlite Deposit, Pleistocene; American Perlite Mine, Inyo County, California, USA) 2
James St. John:
Perlite (Fish Springs Perlite Deposit, Pleistocene; American Perlite Mine, Inyo County, California, USA) 3
