Basalt
Extrusive Mafic Igneous Rock (composed primarily of plagioclase, pyroxene, and olivine)
Category
Browse sedimentary rock (specifically a concretion or possibly a geode) specimens identified by the Rock Identifier community.
Basalt
Extrusive Mafic Igneous Rock (composed primarily of plagioclase, pyroxene, and olivine)
Quartz (specifically Citrine or Yellow Quartzite pebble)
Silicon Dioxide (SiO2)
Basalt River Stone
Basaltic Igneous Rock
Agate
Agate (Cryptocrystalline Variety of Quartz, SiO2)
Basalt
Africite (Mafic Igneous Rock)
Basalt
Extrusive mafic igneous rock
Basalt
Basalt (Aphanitic Mafic Igneous Rock)
Chalcedony (specifically Agate or Water-worn Quartzite)
Silicon Dioxide (SiO2)
Pumice
Pumice (Amorphous volcanic glass)
Basalt
Basalt
Ferruginous Quartz (Iron-stained Quartz)
Silicon Dioxide (SiO2) with Hematite/Goethite inclusions
Basalt
Mafic Igneous Rock
Red Scoria (Lava Rock)
Scoria (Vesicular Basalt/Andesite)
Basalt
Basalt (Igneous Volcanic Rock)
Basalt (with possible weathering or secondary mineral crust)
Basalt (Aphanitic Mafic Igneous Rock)
Basalt
Basalt
Basalt
Basalt (Mafic volcanic rock)
Basalt with Hematite staining
Extrusive mafic igneous rock with Fe2O3
Basalt
Extrusive Mafic Igneous Rock
Quartzite River Pebble
Metamorphosed Quartz Sandstone (SiO2)
Basalt
Basalt
Pumice
Pumice (Vesicular Rhyolite/Andesite)
Fluorite
Calcium Fluoride (CaF2)
Scoria (Basaltic Lava Rock)
Vesicular Basalt
Banded Agate (specifically Sardonyx)
Silicon Dioxide (SiO2) - variety of Chalcedony/Quartz
Basalt
Basalt (Aphanitic-fine grained mafic igneous rock)
Banded Agate (specifically Lake Superior Agate)
Silicon dioxide (SiO2) - Cryptocrystalline Chalcedony
Pumice (Volcanic Rock)
Vesicular volcanic rock (composed largely of amorphous volcanic glass)
Basalt (Weathered Pebble)
Extrusive mafic rock (primarily Plagioclase Feldspar and Pyroxene)
Gneiss (specifically Banded Gneiss)
Gneiss
Granodiorite
Granodiorite
Basalt
Basalt
Basalt (River Cobble)
Basalt (Mafic Extrusive Igneous Rock)
Granodiorite
Granodiorite (Intermediate intrusive igneous rock)
Clear Quartz (or Rock Crystal)
Quartz (SiO₂ - Silicon Dioxide)
Shale
Shale (Consolidated fine-grained clay/silt)
Conglomerate
Conglomerate
Sandstone (with potentially high Feldspar/Arkose content)
Clastic sedimentary rock (SiO2 dominated)
Asphalt (Bituminous Concrete)
Bituminous mix / Anthropogenic conglomerate
Basalt
Basalt (Aphanitic Mafic Volcanic Rock)
Chert (Yellow/Tan Variety)
Chert (SiO2)
Amber-bearing Coal/Sedimentary Rock
Bituminous coal or carbonaceous siltstone with Fossilized Tree Resin (C10H16O)