Rock Identifier

Category

Sedimentary (Volcanic)

Browse sedimentary (volcanic) specimens identified by the Rock Identifier community.

Obsidian (Obsidian (Volcanic Glass)) — igneous

Obsidian

Obsidian (Volcanic Glass)

Obsidian (Black Obsidian) (Obsidian (Volcanic Glass)) — igneous

Obsidian (Black Obsidian)

Obsidian (Volcanic Glass)

Basalt (River Stone) (Mafic volcanic rock) — igneous

Basalt (River Stone)

Mafic volcanic rock

Pumice (Vesicular volcanic glass) — igneous

Pumice

Vesicular volcanic glass

Basalt (Basalt) — igneous

Basalt

Basalt

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

Tumbled Obsidian (possibly Mahogany Obsidian variant) (Volcanic Glass (Amorphous Silicon Dioxide, SiO2)) — igneous

Tumbled Obsidian (possibly Mahogany Obsidian variant)

Volcanic Glass (Amorphous Silicon Dioxide, SiO2)

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

Vesicular Basalt (Scoria) (Vesicular Basalt) — igneous

Vesicular Basalt (Scoria)

Vesicular Basalt

Banded Agate (specifically Carnelian Agate color) (Silicon Dioxide (SiO2) - variety of Chalcedony) — mineral

Banded Agate (specifically Carnelian Agate color)

Silicon Dioxide (SiO2) - variety of Chalcedony

Carnelian (a variety of Chalcedony) (Silicon dioxide (SiO2) with iron oxide impurities) — mineral

Carnelian (a variety of Chalcedony)

Silicon dioxide (SiO2) with iron oxide impurities

Red Scoria (Lava Rock) (Scoria (Extrusive Igneous Rock / Mafic composition)) — igneous

Red Scoria (Lava Rock)

Scoria (Extrusive Igneous Rock / Mafic composition)

Porphyritic Basalt (Amygdaloidal Porphyritic Basalt) — Igneous

Porphyritic Basalt

Amygdaloidal Porphyritic Basalt

Red Jasper (beads) (Silicon Dioxide (SiO2) with iron inclusions) — Sedimentary Rock

Red Jasper (beads)

Silicon Dioxide (SiO2) with iron inclusions

Sedimentary Rock

Shale (sub-type: Carbonaceous Shale) (Lutaceous Sedimentary Rock) — sedimentary

Shale (sub-type: Carbonaceous Shale)

Lutaceous Sedimentary Rock

Amygdaloidal Basalt (Vesicular Basalt with secondary mineral infilling (commonly Zeolite, Calcite, or Quartz)) — igneous

Amygdaloidal Basalt

Vesicular Basalt with secondary mineral infilling (commonly Zeolite, Calcite, or Quartz)

Moss Agate (Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide) — mineral

Moss Agate

Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide

Basalt (Basalt) — igneous

Basalt

Basalt

Scoria (Lava Rock) (Scoria) — igneous

Scoria (Lava Rock)

Scoria

Shale (Fissile mudstone (Shale)) — sedimentary

Shale

Fissile mudstone (Shale)

Scoria (Vesicular Basalt / Scoria (Mafic silicate rock)) — Igneous

Scoria

Vesicular Basalt / Scoria (Mafic silicate rock)

Silty Shale (Silty Shale (Fissile Sedimentary Rock)) — sedimentary

Silty Shale

Silty Shale (Fissile Sedimentary Rock)

Shale (Mudstone (composed primarily of clay minerals like kaolinite, illite, and smectite, with quartz and calcite)) — sedimentary

Shale

Mudstone (composed primarily of clay minerals like kaolinite, illite, and smectite, with quartz and calcite)

Shale (Ferruginous) (Laminated Mudrock (Siliciclastic Sedimentary Rock)) — sedimentary

Shale (Ferruginous)

Laminated Mudrock (Siliciclastic Sedimentary Rock)

Sandstone (Clastic sedimentary rock (primarily SiO2)) — sedimentary

Sandstone

Clastic sedimentary rock (primarily SiO2)

Shale (with Iron Oxide staining) (Fissile Mudstone (primarily Quartz and Clay minerals)) — sedimentary

Shale (with Iron Oxide staining)

Fissile Mudstone (primarily Quartz and Clay minerals)

Basalt (Extrusive mafic igneous rock) — igneous

Basalt

Extrusive mafic igneous rock

Brachiopod Fossil in Limestone (Phylum Brachiopoda (likely Order Spiriferida), CaCO3 (Calcite)) — sedimentary

Brachiopod Fossil in Limestone

Phylum Brachiopoda (likely Order Spiriferida), CaCO3 (Calcite)

Scoria (Vesicular Basalt) (Scoria (Extrusive Igneous Rock)) — igneous

Scoria (Vesicular Basalt)

Scoria (Extrusive Igneous Rock)

Amethyst (SiO2 (Amethyst is a variety of Quartz)) — mineral

Amethyst

SiO2 (Amethyst is a variety of Quartz)

Obsidian (Volcanic Glass (SiO2 rich)) — igneous

Obsidian

Volcanic Glass (SiO2 rich)

Basalt with Scoria (Amygdaloidal Basalt / Vesicular Basalt) — igneous

Basalt with Scoria

Amygdaloidal Basalt / Vesicular Basalt

Porphyritic Andesite (Porphyritic intermediate volcanic rock (Andesite)) — Igneous

Porphyritic Andesite

Porphyritic intermediate volcanic rock (Andesite)

Pumice (Pumice (a vesicular volcanic glass)) — igneous

Pumice

Pumice (a vesicular volcanic glass)

Agate (Agate (a variety of Chalcedony, SiO2)) — Mineral

Agate

Agate (a variety of Chalcedony, SiO2)

Carnelian (Carnelian (a variety of Chalcedony, SiO2)) — Mineral

Carnelian

Carnelian (a variety of Chalcedony, SiO2)

Yellow Chalcedony (Chalcedony (a cryptocrystalline variety of Quartz, SiO₂)) — Mineral

Yellow Chalcedony

Chalcedony (a cryptocrystalline variety of Quartz, SiO₂)

Banded Agate (specifically Sardonyx) (Silicon Dioxide (SiO2) - variety of Chalcedony/Quartz) — mineral

Banded Agate (specifically Sardonyx)

Silicon Dioxide (SiO2) - variety of Chalcedony/Quartz

Basalt (Basalt (Mafic volcanic rock)) — igneous

Basalt

Basalt (Mafic volcanic rock)

Dark Igneous Rock (Likely Basalt or Diabase) (Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.) — Igneous

Dark Igneous Rock (Likely Basalt or Diabase)

Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Sedimentary Breccia (Breccia (Clastic Sedimentary Rock)) — sedimentary

Sedimentary Breccia

Breccia (Clastic Sedimentary Rock)

Banded Agate (Silicon Dioxide (SiO2)) — mineral

Banded Agate

Silicon Dioxide (SiO2)