Rock Identifier

Category

Igneous, Specifically Volcanic

Browse igneous, specifically volcanic specimens identified by the Rock Identifier community.

Weathered Volcanic Rock (possibly Rhyolite or Andesite Pebble) (Volcanic rock (e.g., Rhyolite or Andesite, specific identification would require thin section analysis or chemical assay). Mineral composition: Primarily feldspars (orthoclase and/or plagioclase), quartz (in rhyolite), micas, amphiboles, and sometimes pyroxenes.) — Igneous, specifically volcanic/extrusive (possibly Rhyolite or Andesite)

Weathered Volcanic Rock (possibly Rhyolite or Andesite Pebble)

Volcanic rock (e.g., Rhyolite or Andesite, specific identification would require thin section analysis or chemical assay). Mineral composition: Primarily feldspars (orthoclase and/or plagioclase), quartz (in rhyolite), micas, amphiboles, and sometimes pyroxenes.

Igneous, specifically volcanic/extrusive (possibly Rhyolite or Andesite)

Carnelian (Cryptocrystalline Quartz (SiO2)) — mineral

Carnelian

Cryptocrystalline Quartz (SiO2)

Amethyst (Rough) (Silicon Dioxide with iron impurities (SiO2)) — mineral

Amethyst (Rough)

Silicon Dioxide with iron impurities (SiO2)

Amygdaloidal Basalt (Amygdaloidal Basalt) — igneous

Amygdaloidal Basalt

Amygdaloidal Basalt

Obsidian (Volcanic Glass (SiO2 + minor impurities)) — igneous

Obsidian

Volcanic Glass (SiO2 + minor impurities)

Polished Basalt (Basalt (Mafic volcanic rock)) — Igneous

Polished Basalt

Basalt (Mafic volcanic rock)

Amethyst (Amethyst (Silicon Dioxide - SiO2 with impurities of iron)) — mineral

Amethyst

Amethyst (Silicon Dioxide - SiO2 with impurities of iron)

Carnelian (Carnelian (SiO2)) — mineral

Carnelian

Carnelian (SiO2)

Bumblebee Jasper (Fossiliferous Volcanic Rock (composed of Calcium Carbonate, Manganese Oxides, and Arsenic Sulfides)) — igneous

Bumblebee Jasper

Fossiliferous Volcanic Rock (composed of Calcium Carbonate, Manganese Oxides, and Arsenic Sulfides)

Banded Agate (Cryptocrystalline Quartz (SiO2)) — mineral

Banded Agate

Cryptocrystalline Quartz (SiO2)

Mahogany Obsidian (Volcanic Glass with Hematite/Magnetite inclusions (SiO2)) — igneous

Mahogany Obsidian

Volcanic Glass with Hematite/Magnetite inclusions (SiO2)

Jasper Agate (Silicon dioxide (SiO2)) — mineral

Jasper Agate

Silicon dioxide (SiO2)

Dalmatian Stone (Dalmatian Jasper (Aphanitic Igneous Rock with Arfvedsonite inclusions)) — igneous

Dalmatian Stone

Dalmatian Jasper (Aphanitic Igneous Rock with Arfvedsonite inclusions)

Bumblebee Jasper (Volcanic Tuff (mixture of Quartz, Sulfur, Hematite, and Orpiment)) — igneous

Bumblebee Jasper

Volcanic Tuff (mixture of Quartz, Sulfur, Hematite, and Orpiment)

Basalt with Magnetite (Crystalline Basalt (Primarily Plagioclase and Pyroxene) with Magnetite (Fe3O4)) — igneous

Basalt with Magnetite

Crystalline Basalt (Primarily Plagioclase and Pyroxene) with Magnetite (Fe3O4)

Mahogany Obsidian (Obsidian (Volcanic Glass) with Hematite or Magnetite inclusions, SiO2 (Silicon Dioxide)) — igneous

Mahogany Obsidian

Obsidian (Volcanic Glass) with Hematite or Magnetite inclusions, SiO2 (Silicon Dioxide)

Moonstone (Green Moonstone / Garnierite) (Potassium Aluminum Silicate (KAlSi3O8) with inclusions of Garnierite) — mineral

Moonstone (Green Moonstone / Garnierite)

Potassium Aluminum Silicate (KAlSi3O8) with inclusions of Garnierite

Amygdaloidal Basalt with Epidote/Chlorite (Basalt (containing (Ca2(Al2Fe3+)(SiO4)(Si2O7)O(OH)))) — igneous

Amygdaloidal Basalt with Epidote/Chlorite

Basalt (containing (Ca2(Al2Fe3+)(SiO4)(Si2O7)O(OH)))

Basalt (Basalt (composition of plagioclase feldspar and pyroxene)) — Igneous

Basalt

Basalt (composition of plagioclase feldspar and pyroxene)

Green Porphyry (Flowerstone) (Porphyritic Andesite or Basalt) — igneous

Green Porphyry (Flowerstone)

Porphyritic Andesite or Basalt

Mahogany Obsidian (Obsidian (Volcanic Glass with Hematite/Magnetite inclusions), SiO2) — igneous

Mahogany Obsidian

Obsidian (Volcanic Glass with Hematite/Magnetite inclusions), SiO2

Blue Lace Agate (Chalcedony (SiO2) with trace minerals) — mineral

Blue Lace Agate

Chalcedony (SiO2) with trace minerals

Basalt with Vesicle/Vug (Basalt (Aphanitic Mafic Igneous Rock)) — igneous

Basalt with Vesicle/Vug

Basalt (Aphanitic Mafic Igneous Rock)

Mahogany Obsidian Arrowhead (Obsidian (volcanic glass) with Hematite inclusions) — igneous

Mahogany Obsidian Arrowhead

Obsidian (volcanic glass) with Hematite inclusions

Crazy Lace Agate (Chalcedony (Silicon Dioxide, SiO2)) — mineral

Crazy Lace Agate

Chalcedony (Silicon Dioxide, SiO2)

Apache Tear (Hydrated Obsidian (Natural Volcanic Glass)) — igneous

Apache Tear

Hydrated Obsidian (Natural Volcanic Glass)

Apache Tear (Obsidian (Hydrated Volcanic Glass)) — igneous

Apache Tear

Obsidian (Hydrated Volcanic Glass)

Yellow Agate (Agate (Varietal form of Chalcedony/Quartz, SiO2)) — mineral

Yellow Agate

Agate (Varietal form of Chalcedony/Quartz, SiO2)

Basalt Porphyry (Porphyritic Basalt) — igneous

Basalt Porphyry

Porphyritic Basalt

Greenstone Porphyry (Porphyritic Metavolcanic Rock) — igneous

Greenstone Porphyry

Porphyritic Metavolcanic Rock

Chalcedony (Agate/Chert) (Silicon Dioxide (SiO2)) — mineral

Chalcedony (Agate/Chert)

Silicon Dioxide (SiO2)

Apricot Agate (Silicon Dioxide (SiO2) - Chalcedony variety) — mineral

Apricot Agate

Silicon Dioxide (SiO2) - Chalcedony variety

Obsidian (Apache Tear) (Volcanic Glass (SiO2)) — igneous

Obsidian (Apache Tear)

Volcanic Glass (SiO2)

Blue Lace Agate (Silicon Dioxide (SiO₂), a variety of Chalcedony) — mineral

Blue Lace Agate

Silicon Dioxide (SiO₂), a variety of Chalcedony

Basalt River Stone (Basalt (Mafic volcanic rock, primarily Plagioclase and Pyroxene)) — igneous

Basalt River Stone

Basalt (Mafic volcanic rock, primarily Plagioclase and Pyroxene)

Greenstone (Greenschist (metamorphosed mafic igneous rock)) — metamorphic

Greenstone

Greenschist (metamorphosed mafic igneous rock)

Blue Chalcedony (Blue Lace Agate variety) (Silicon Dioxide (SiO₂)) — mineral

Blue Chalcedony (Blue Lace Agate variety)

Silicon Dioxide (SiO₂)

Olivine (Peridotite/Dunite) (Olivine (Mg,Fe)2SiO4 within Peridotite) — igneous

Olivine (Peridotite/Dunite)

Olivine (Mg,Fe)2SiO4 within Peridotite

Mahogany Obsidian (Volcanic glass (SiO2 with Hematite or Magnetite inclusions)) — igneous

Mahogany Obsidian

Volcanic glass (SiO2 with Hematite or Magnetite inclusions)

Chalcedony (specifically Agate or Moonstone-like Quartz) (Silicon Dioxide (SiO2)) — mineral

Chalcedony (specifically Agate or Moonstone-like Quartz)

Silicon Dioxide (SiO2)

Porphyry (specifically Porphyritic Rhyolite or Andesite) (Porphyritic Igneous Rock (composed of Phenocrysts in an Aphanitic groundmass)) — igneous

Porphyry (specifically Porphyritic Rhyolite or Andesite)

Porphyritic Igneous Rock (composed of Phenocrysts in an Aphanitic groundmass)

Thunderegg (specifically a Jasper/Agate-filled Geode nodule) (Silicon Dioxide (SiO2) within Rhyolitic Matrix) — igneous

Thunderegg (specifically a Jasper/Agate-filled Geode nodule)

Silicon Dioxide (SiO2) within Rhyolitic Matrix