Rock Identifier

Category

Sedimentary (Volcanic)

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

Quartz-veined Siltstone (Siltstone with Quartz (SiO2) veins) — sedimentary

Quartz-veined Siltstone

Siltstone with Quartz (SiO2) veins

Black Obsidian (Obsidian (Volcanic glass), 70–75% SiO2) — igneous

Black Obsidian

Obsidian (Volcanic glass), 70–75% SiO2

Mahogany Obsidian (Volcanic Glass (predominantly SiO2 with Fe2O3 inclusions)) — igneous

Mahogany Obsidian

Volcanic Glass (predominantly SiO2 with Fe2O3 inclusions)

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

Mahogany Obsidian

Obsidian (Volcanic Glass) with Hematite/Magnetite inclusions

Peridot (Olivine (Mg, Fe)2SiO4) — mineral

Peridot

Olivine (Mg, Fe)2SiO4

Milky Quartz (Silicon Dioxide (SiO2)) — mineral

Milky Quartz

Silicon Dioxide (SiO2)

Basalt (Mafic Igneous Rock (composed primarily of Pyroxene and Plagioclase Feldspar)) — igneous

Basalt

Mafic Igneous Rock (composed primarily of Pyroxene and Plagioclase Feldspar)

Banded Agate (Carnelian type) (Agate (Cryptocrystalline Quartz, SiO2)) — mineral

Banded Agate (Carnelian type)

Agate (Cryptocrystalline Quartz, SiO2)

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

Blue Lace Agate

Silicon Dioxide (SiO₂), a variety of Chalcedony

Ocean Jasper (Orbicular Jasper (Silicon Dioxide with impurities), SiO2) — mineral

Ocean Jasper

Orbicular Jasper (Silicon Dioxide with impurities), SiO2

Gold-bearing Quartz with Iron Oxides (Quartz (SiO2) with Limonite/Goethite (FeO(OH)) and Pyrite (FeS2)) — mineral

Gold-bearing Quartz with Iron Oxides

Quartz (SiO2) with Limonite/Goethite (FeO(OH)) and Pyrite (FeS2)

Basalt (Basalt) — igneous

Basalt

Basalt

Basalt River Stone (Tumbled) (Basalt (Mafic Extrusive Igneous Rock)) — igneous

Basalt River Stone (Tumbled)

Basalt (Mafic Extrusive Igneous Rock)

Basalt Pebble (Extrusive mafic igneous rock) — igneous

Basalt Pebble

Extrusive mafic igneous rock

Olivine ((Mg,Fe)2SiO4 (Magnesium Iron Silicate)) — mineral

Olivine

(Mg,Fe)2SiO4 (Magnesium Iron Silicate)

Vesicular Basalt (Basalt with vesicular texture) — igneous

Vesicular Basalt

Basalt with vesicular texture

Milky Quartz (Silicon Dioxide (SiO2)) — mineral

Milky Quartz

Silicon Dioxide (SiO2)

Agate (Cryptocrystalline Quartz (SiO2)) — mineral

Agate

Cryptocrystalline Quartz (SiO2)

Vesicular Basalt (Basalt (with vesicular texture)) — igneous

Vesicular Basalt

Basalt (with vesicular texture)

Vesicular Basalt (Basalt) — igneous

Vesicular Basalt

Basalt

Basalt River Stone (Basalt) — igneous

Basalt River Stone

Basalt

Basalt with Amygdules (Amygdaloidal Basalt) — igneous

Basalt with Amygdules

Amygdaloidal Basalt

Basalt (River Pebble) (Basalt) — igneous

Basalt (River Pebble)

Basalt

Blue Lace Agate (often dyed) (Silicon dioxide (SiO2) - variety of chalcedony) — mineral

Blue Lace Agate (often dyed)

Silicon dioxide (SiO2) - variety of chalcedony

Apache Tear (Obsidian) (Volcanic glass (SiO2 - Silicon Dioxide)) — igneous

Apache Tear (Obsidian)

Volcanic glass (SiO2 - Silicon Dioxide)

Obsidian (Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)) — Igneous

Obsidian

Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)

Snowflake Obsidian (Volcanic Glass with Spherulite Inclusions (70-75% SiO2)) — igneous

Snowflake Obsidian

Volcanic Glass with Spherulite Inclusions (70-75% SiO2)

Sedimentary rock with quartz veining (Laminated siltstone or mudstone with hydrothermal quartz veins) — sedimentary

Sedimentary rock with quartz veining

Laminated siltstone or mudstone with hydrothermal quartz veins

Sedimentary Sandstone (Sandstone Slab) (Arenite (SiO2 with Fe2O3 staining)) — sedimentary

Sedimentary Sandstone (Sandstone Slab)

Arenite (SiO2 with Fe2O3 staining)

Fossil Shell in Sedimentary Matrix (Bivalvia (fossil) in Calcium Carbonate Matrix) — sedimentary

Fossil Shell in Sedimentary Matrix

Bivalvia (fossil) in Calcium Carbonate Matrix

Snowflake Obsidian (Volcanic glass (SiO2) with Cristobalite (SiO2) inclusions) — igneous

Snowflake Obsidian

Volcanic glass (SiO2) with Cristobalite (SiO2) inclusions

Mahogany Obsidian (Volcanic Glass with Hematite/Magnetite (SiO2 + Fe2O3)) — igneous

Mahogany Obsidian

Volcanic Glass with Hematite/Magnetite (SiO2 + Fe2O3)

Basalt with Iron Oxidation (Lattice/Veined) (Mafic Volcanic Rock (principally Plagioclase and Pyroxene)) — igneous

Basalt with Iron Oxidation (Lattice/Veined)

Mafic Volcanic Rock (principally Plagioclase and Pyroxene)

Banded Agate (White Agate) (Chalcedony (Silicon Dioxide, SiO2)) — mineral

Banded Agate (White Agate)

Chalcedony (Silicon Dioxide, SiO2)

Diorite (Diorite (Intermediate intrusive igneous rock)) — igneous

Diorite

Diorite (Intermediate intrusive igneous rock)

Pumice (Pumice (Volcanic glass with vesicular texture)) — igneous

Pumice

Pumice (Volcanic glass with vesicular texture)

Cullet Glass (Slag Glass) (Amorphous Silicon Dioxide (Industrial Byproduct)) — mineraloid

Cullet Glass (Slag Glass)

Amorphous Silicon Dioxide (Industrial Byproduct)

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

Pumice

Pumice (a highly vesicular volcanic glass)

Amygdaloidal Basalt with Zeolite/Quartz Infill (Amygdaloidal Basalt (Host: (Mg,Fe)2SiO4 / CaAl2Si2O8; Infill: SiO2 or Na2Al2Si3O10·2H2O)) — igneous

Amygdaloidal Basalt with Zeolite/Quartz Infill

Amygdaloidal Basalt (Host: (Mg,Fe)2SiO4 / CaAl2Si2O8; Infill: SiO2 or Na2Al2Si3O10·2H2O)

Thunderegg (Agetized Geode nodule) (Rhyolitic Agate Nodule (SiO2 filling volcanic cavities)) — igneous

Thunderegg (Agetized Geode nodule)

Rhyolitic Agate Nodule (SiO2 filling volcanic cavities)

Black Obsidian (Obsidian (Amorphous volcanic glass, SiO2)) — igneous

Black Obsidian

Obsidian (Amorphous volcanic glass, SiO2)

Basalt with Quartz Veining (Basalt (Mafic Volcanic Rock with SiO2)) — igneous

Basalt with Quartz Veining

Basalt (Mafic Volcanic Rock with SiO2)