River Stone (River Pebbles)
Alluvial Deposit (typically Quartzite, Sandstone, or Granite clasts)
sedimentary
Category
Sedimentary (Secondary Formation)
Browse sedimentary (secondary formation) specimens identified by the Rock Identifier community.
Chert (variations include Flint/Novaculite)
Chert (formula: SiO2)
sedimentary
Chert (often called Flint or River Rock)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Jasper (Tiger Eye variety transition)
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Sandstone
Arenite (primarily SiO2 with trace Fe2O3)
sedimentary
Jasper
Silicon Dioxide (SiO2)
Mineral
Chalk
CaCO3 (primarily Calcium Carbonate), biogenic sedimentary rock
Sedimentary
Shale or Siltstone
Sedimentary Rock (Siliciclastic)
sedimentary
Muscovite Mica
Muscovite - KAl2(AlSi3O10)(OH)2
mineral
Chert (Arrowhead Fragment)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Banded Onyx (Calcite Marble)
Calcite (CaCO3) - Trap-rock or Cave Onyx
sedimentary
Red Jasper
Jasper (SiO2 with Fe2O3 inclusions)
sedimentary
Chalcedony (or a variety of Chalcedony, likely Agate or Jasper)
Chalcedony (SiO₂)
Mineral (or mineraloid if microcrystalline)
Quartz
Silicon Dioxide (SiO2)
Mineral
Quartz
Silicon Dioxide (SiO₂)
Mineral
Banded Chert / Banded Jasper (likely a variety of Chert/Chalcedony)
Chert (microcrystalline quartz)
Metamorphic Rock
Fossiliferous Limestone
Limestone (composed primarily of calcite with included fossils CaCO3)
Sedimentary
Chert (specifically Gray/Tan Bedded Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Agate (specifically Carnelian Agate or Lake Superior style Agate)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Magnetite
Magnetite (Iron(II,III) oxide, Fe3O4)
mineral
Rhodochrosite
Manganese Carbonate (MnCO3)
mineral
Gneiss
Gneiss
metamorphic
Sandstone (likely Siltstone or Mudstone variety)
Clastic Sedimentary Rock (primarily SiO2 with iron oxides)
sedimentary
Sandstone (Red)
Arenite (primarily SiO2 with Iron Oxide staining)
sedimentary
Moqui Marble (Concretion)
Iron oxide concretion (Goethite/Hematite and Sandstone)
sedimentary
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Brecciated Jasper
Silicon Dioxide (SiO2) with Hematite and Quartz inclusions
sedimentary
Chert (varieties include Flint and Jasper)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Puddingstone (Jasper Conglomerate)
Conglomerate (specific type: Jasper Conglomerate or Hertfordshire Puddingstone)
Sedimentary
Green Aventurine
Aventurine Quartz (SiO2 with inclusions of Fuchsite)
metamorphic
Red Chert (Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Banded Chert (Flint/Jasper variety)
Microcrystalline Quartz (SiO2)
sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Iron Oxide inclusions
mineral
Diorite (possibly fine-grained variety or a related intermediate intrusive rock like a felsic gabbro or a dark granodiorite)
Diorite (Igneous rock, intrusive, intermediate composition)
Igneous Rock
Sandstone (Quartzose)
Arenite (Siliciclastic sedimentary rock)
sedimentary
Chert Concretion (with typical hematite/limonite staining)
Sedimentary Concretion (SiO2 with FeO(OH)⋅nH2O)
sedimentary
Clear Quartz (Rock Crystal)
Quartz (SiO₂)
Mineral
Agate (or Chalcedony)
SiO2 (Silicon Dioxide) - a cryptocrystalline variety of quartz
Mineral
Banded Iron Formation (Jasper-Hematite)
Banded Iron Formation (BIF); composition primarily Hematite (Fe2O3) and Chalcedony/Quartz (SiO2)
sedimentary
Painted River Rock
Anthropogenic-modified Siliciclastic Sedimentary Rock
Sedimentary