Basalt
Extrusive mafic igneous rock
Category
Browse sedimentary rock (specifically a concretion or possibly a geode) specimens identified by the Rock Identifier community.
Basalt
Extrusive mafic igneous rock
Sandstone (Quartzite-rich River Cobble)
Clastic sedimentary rock (primarily SiO2)
Sandstone
Arenite (primarily SiO2)
Sandstone
Arenite
River Pebble (Likely Chert or Fine-Grained Sandstone/Quartzite)
Siliciclastic clast (likely Chert or Quartzarenite/Quartzite pebble)
Sandstone
Arenite (primarily SiO2 with various cementing agents)
Sandstone
Arenite (composed primarily of SiO2)
Sandstone (Ferruginous)
Arenite (SiO2 with Iron Oxide impurities)
Sandstone (likely Quartzose Sandstone)
Arenite (SiO2 principal composition)
Chert (Chert / Flint)
Silicon dioxide (SiO2) - Microcrystalline quartz
Chert (Nodule)
Silicon Dioxide (SiO2)
Pyrite in Shale
Iron Sulfide (FeS2) in Argillaceous Shale
Ferruginous Sandstone (with Iron Oxide staining)
Clastic Sedimentary Rock - Quartz Arenite/Wacke
Greywacke
Lithic Sandstone (Greywacke - (SiO2+Al2O3+Fe2O3))
Chert (Nodule)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Limestone
Calcareous sedimentary rock (primarily Calcium Carbonate, CaCO3)
Bituminous Coal
Organic Sedimentary Rock (Carbon-based)
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily SiO2)
Sandstone
Arenite (primarily SiO2)
Sandstone
Arenite (primarily SiO2)
Basalt
Basalt (Igneous Volcanic Rock)
Sandstone
Arenite (composed primarily of SiO2)
Chert with Asphaltum (or Tar)
Silica (SiO2) with natural Bitumen/Asphaltum
Botryoidal Chalcedony
Chalcedony (SiO2)
Sandstone
Arenite (composed primarily of SiO2)
Sandstone (Quartzose Sandstone)
Clastic sedimentary rock (primarily SiO2)
Sandstone (with potential trace fossils)
Clastic sedimentary rock (primarily SiO2)
Pumice
Pumice (a highly vesicular amorphous volcanic glass)
Labradorite
Labradorite (a variety of Plagioclase Feldspar), Na(AlSi3O8) to Ca(Al2Si2O8)
Sandstone (likely Quartzose Sandstone with mineral staining)
Arenite (composed mainly of SiO2)
Dalmatian Stone
Dalmatian Jasper (Aplitic Rock)
Limestone (with Iron-Oxide staining)
Sedimentary Calcium Carbonate (CaCO3)
Greywacke (River Pebble with Quartz Veins)
Greywacke (Indurated Sandstone); Veins: SiO2 (Quartz)
Sandstone (likely Fossiliferous)
Arenite / Fossiliferous Sandstone (SiO2 composition)
Sandstone
Clastic Sedimentary Rock (primarily SiO2)
Chert (Gravel)
Microcrystalline Quartz (SiO2)
Chert (Gravel / Pebble)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Greywacke
Greywacke sandstone
Sand (Construction Grade)
Unconsolidated siliciclastic sediment (primarily SiO2)
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
Sandstone (Quartz Arenite)
Sandstone (Chemical formula: primarily SiO2)
Jasper or Chalcedony
Microcrystalline Quartz (SiO2)