Rock Identifier

Category

Organic Crystal (Mineraloid)

Browse organic crystal (mineraloid) specimens identified by the Rock Identifier community.

Petrified Wood (Silicified Wood (primarily SiO2 - Silicon Dioxide)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Water and Silt (Sedimentary Environment) (Suspended Sediment / H2O (dihydrogen monoxide)) — sedimentary

Water and Silt (Sedimentary Environment)

Suspended Sediment / H2O (dihydrogen monoxide)

Fossiliferous Limestone (Limestone (CaCO3 with Limonite/Goethite staining)) — sedimentary

Fossiliferous Limestone

Limestone (CaCO3 with Limonite/Goethite staining)

Petrified Wood (Silicified wood (principally Silicon Dioxide, SiO2)) — sedimentary

Petrified Wood

Silicified wood (principally Silicon Dioxide, SiO2)

Sandstone (Ferruginous) (Arenite (primarily SiO2 with Fe2O3 cement)) — sedimentary

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 cement)

Graphite (Graphite (Native Carbon, C)) — metamorphic

Graphite

Graphite (Native Carbon, C)

Chert (Nodule) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Nodule)

Silicon Dioxide (SiO2)

Chert (Jasper variety) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Likely tumbled jasper or chert specimens (Microcrystalline quartz (SiO₂), commonly jasper/chert; exact identification is uncertain from the photograph) — sedimentary

Likely tumbled jasper or chert specimens

Microcrystalline quartz (SiO₂), commonly jasper/chert; exact identification is uncertain from the photograph

Jasper (Green/Yellow Moss Jasper) (Silicon Dioxide (SiO2)) — mineral

Jasper (Green/Yellow Moss Jasper)

Silicon Dioxide (SiO2)

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

Shale (sub-type: Carbonaceous Shale)

Lutaceous Sedimentary Rock

Petrified Wood (Silicon Dioxide Fossilized Wood (SiO2)) — fossil

Petrified Wood

Silicon Dioxide Fossilized Wood (SiO2)

Banded Chert (Flint/Jasper variety) (Microcrystalline Quartz (SiO2)) — sedimentary

Banded Chert (Flint/Jasper variety)

Microcrystalline Quartz (SiO2)

Petrified Wood (Silicified Wood (SiO2)) — mineral

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood (Silicified wood (Quartz/Chalcedony replacement)) — fossil

Petrified Wood

Silicified wood (Quartz/Chalcedony replacement)

Yellow Chalcedony (common opal or chert variant) (Silicon Dioxide (SiO2)) — sedimentary (mineraloid/microcrystalline quartz)

Yellow Chalcedony (common opal or chert variant)

Silicon Dioxide (SiO2)

sedimentary (mineraloid/microcrystalline quartz)

Chert (Flint variety) (Microcrystalline Silica (SiO2)) — sedimentary

Chert (Flint variety)

Microcrystalline Silica (SiO2)

Ironstone / limonite-rich concretion (Hydrated iron oxides, chiefly limonite/goethite (FeO(OH)·nH₂O), possibly with hematite) — mineral

Ironstone / limonite-rich concretion

Hydrated iron oxides, chiefly limonite/goethite (FeO(OH)·nH₂O), possibly with hematite

Amber (Cherry or Red variety) (Succinite (with various trace amounts of organic compounds)) — Organic Gemstone (not a rock)

Amber (Cherry or Red variety)

Succinite (with various trace amounts of organic compounds)

Organic Gemstone (not a rock)

Bituminous Coal (Organic-rich sedimentary rock (Complex hydrocarbons)) — sedimentary

Bituminous Coal

Organic-rich sedimentary rock (Complex hydrocarbons)

Petrified Wood (Silicified Wood (primarily SiO2)) — fossil

Petrified Wood

Silicified Wood (primarily SiO2)

Chert (Brown variety / Common Jasper) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Brown variety / Common Jasper)

Microcrystalline Quartz (SiO2)

Petrified Wood (Silicified wood (permineralized wood)) — fossil

Petrified Wood

Silicified wood (permineralized wood)

Quartzite Pebble with Pyrite Coating (SiO2 (Quartz) with FeS2 (Pyrite) inclusions or surface coating) — metamorphic

Quartzite Pebble with Pyrite Coating

SiO2 (Quartz) with FeS2 (Pyrite) inclusions or surface coating

Ironstone Concretion / Goethite-Hematite Geode (Goethite / Hematite Concretion (Fe3O4 / FeO(OH) / Fe2O3)) — sedimentary

Ironstone Concretion / Goethite-Hematite Geode

Goethite / Hematite Concretion (Fe3O4 / FeO(OH) / Fe2O3)

Shale (Fissile Clay-dominant Mudrock (SiO2, Al2O3, K2O, Na2O, CaO, MgO)) — sedimentary

Shale

Fissile Clay-dominant Mudrock (SiO2, Al2O3, K2O, Na2O, CaO, MgO)

Chert (Chert Nodule) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Chert Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Yellow Jasper (Mookaite style) (Silicon Dioxide (SiO2) with Goethite/Hematite inclusions) — sedimentary

Yellow Jasper (Mookaite style)

Silicon Dioxide (SiO2) with Goethite/Hematite inclusions

Chert (Cherty Flint/Jasper variety) (Microcrystalline or cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Cherty Flint/Jasper variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Petrified Wood (Silicified Wood (primarily SiO2)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2)

Anthracite Coal (Anthracite) — metamorphic

Anthracite Coal

Anthracite

Chert (Tan/Grey variety) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Tan/Grey variety)

Silicon Dioxide (SiO2)

Petrified Wood (Silicified Wood (SiO2)) — metamorphic

Petrified Wood

Silicified Wood (SiO2)

Chert (Jasper/Flint variety) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Petrified Wood (Silicified Wood (SiO2)) — mineral

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood (Silicified Wood (primarily Chalcedony or Quartz, SiO2)) — sedimentary

Petrified Wood

Silicified Wood (primarily Chalcedony or Quartz, SiO2)

Chert (Flint) (Chert (Cryptocrystalline variety of Quartz, SiO2)) — sedimentary

Chert (Flint)

Chert (Cryptocrystalline variety of Quartz, SiO2)

Chert (specifically Iron-stained River Cobble) (Silicon Dioxide (SiO2)) — sedimentary

Chert (specifically Iron-stained River Cobble)

Silicon Dioxide (SiO2)

Red Jasper (Silicon Dioxide (SiO2) with Iron Oxide inclusions) — sedimentary

Red Jasper

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Red Jasper (Jasper (Silicon Dioxide with Iron inclusions - SiO2)) — Sedimentary/Metamorphic

Red Jasper

Jasper (Silicon Dioxide with Iron inclusions - SiO2)

Sedimentary/Metamorphic

Amber (Succinite (fossilized tree resin, C10H16O)) — fossil

Amber

Succinite (fossilized tree resin, C10H16O)

Chert (variant Flint/Jasper) (Microcrystalline Opaline Silica (SiO2)) — sedimentary

Chert (variant Flint/Jasper)

Microcrystalline Opaline Silica (SiO2)