Rock Identifier

Category

Organic (Geological Relative)

Browse organic (geological relative) specimens identified by the Rock Identifier community.

Chert (Red Jasper) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Red Jasper)

Microcrystalline Quartz (SiO2)

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

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

White Marble (Calcite-rich Metasomatized Carbonate (CaCO3)) — metamorphic

White Marble

Calcite-rich Metasomatized Carbonate (CaCO3)

Amethyst cabochon ring (Amethyst, purple quartz (SiO₂), colored primarily by iron-related defects and irradiation) — gemstone

Amethyst cabochon ring

Amethyst, purple quartz (SiO₂), colored primarily by iron-related defects and irradiation

Travertine (Travertine (a terrestrial form of Limestone, CaCO3)) — sedimentary

Travertine

Travertine (a terrestrial form of Limestone, CaCO3)

Pumice (Vesicular Rhyolite or Dacite) — igneous

Pumice

Vesicular Rhyolite or Dacite

Petrified Wood (Silicified Wood (SiO2)) — fossil

Petrified Wood

Silicified Wood (SiO2)

Agatized Fossil (Druzy Agate) (Silicon Dioxide (SiO2) replacing organic matter) — sedimentary

Agatized Fossil (Druzy Agate)

Silicon Dioxide (SiO2) replacing organic matter

Chert with Fossil Brachiopod (Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion) — sedimentary

Chert with Fossil Brachiopod

Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion

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

Petrified Wood

Silicified Wood (primarily SiO2)

Dark mafic rock, likely basalt (Basalt; chiefly plagioclase feldspar and pyroxene, with possible olivine and iron oxides) — igneous

Dark mafic rock, likely basalt

Basalt; chiefly plagioclase feldspar and pyroxene, with possible olivine and iron oxides

Banded Chert (River Pebble) (Microcrystalline Quartz (SiO2)) — sedimentary

Banded Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Likely bituminous coal (Coal, predominantly carbon-rich organic matter; exact rank cannot be confirmed from the image) — sedimentary

Likely bituminous coal

Coal, predominantly carbon-rich organic matter; exact rank cannot be confirmed from the image

Graphitic schist (probable) (Graphite-bearing mica schist; chiefly quartz, mica, and graphite) — metamorphic

Graphitic schist (probable)

Graphite-bearing mica schist; chiefly quartz, mica, and graphite

Tumbled black obsidian (Obsidian (volcanic glass), primarily rhyolitic silica glass) — igneous

Tumbled black obsidian

Obsidian (volcanic glass), primarily rhyolitic silica glass

Limonitic Scoria (Vesicular Basalt with Iron Staining) (Highly vesicular basalt heavily stained by Limonite [FeO(OH)·nH2O]) — igneous

Limonitic Scoria (Vesicular Basalt with Iron Staining)

Highly vesicular basalt heavily stained by Limonite [FeO(OH)·nH2O]

Green Chert (Microcrystalline Quartz (SiO2)) — sedimentary

Green Chert

Microcrystalline Quartz (SiO2)

Chert (Concretion or Nodular Variety) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Concretion or Nodular Variety)

Microcrystalline Quartz (SiO2)

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

Petrified Wood

Silicified Wood (primarily SiO2)

Petrified Wood (Silicified wood (primarily Silicon Dioxide, SiO2)) — metamorphic

Petrified Wood

Silicified wood (primarily Silicon Dioxide, SiO2)

Mixed Gemstone and Mineral Collection (Silicon Dioxide (SiO2) based minerals and others) — mineral

Mixed Gemstone and Mineral Collection

Silicon Dioxide (SiO2) based minerals and others

Chert with Limestone Cortex (Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3)) — sedimentary

Chert with Limestone Cortex

Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3)

Yellow Jasper (Jasper (Silicon Dioxide, SiO2 plus various mineral impurities)) — sedimentary

Yellow Jasper

Jasper (Silicon Dioxide, SiO2 plus various mineral impurities)

Coral Fossil (Hexagonaria) (Hexagonaria sp. (Silica-replaced)) — fossil

Coral Fossil (Hexagonaria)

Hexagonaria sp. (Silica-replaced)

Fossiliferous Sandstone Pebble (with Crinoid / Shell Impression) (Sandstone containing fossiliferous inclusions (SiO2 matrix with calcite/silica cast fossil)) — sedimentary

Fossiliferous Sandstone Pebble (with Crinoid / Shell Impression)

Sandstone containing fossiliferous inclusions (SiO2 matrix with calcite/silica cast fossil)

Amber (Copal) (Succiniferous Resin) — mineraloid

Amber (Copal)

Succiniferous Resin

Yellow calcite (honey calcite) (Calcite, calcium carbonate (CaCO₃)) — mineral

Yellow calcite (honey calcite)

Calcite, calcium carbonate (CaCO₃)

Fossiliferous Limestone (Biogenic Sedimentary Rock (CaCO3)) — sedimentary

Fossiliferous Limestone

Biogenic Sedimentary Rock (CaCO3)

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

Petrified Wood

Silicified Wood (primarily SiO2)

Moqui Marbles (Iron Oxide Concretion (Hematite/Goethite)) — sedimentary

Moqui Marbles

Iron Oxide Concretion (Hematite/Goethite)

Fossilized Coral (Cnidaria (Anthozoa), often replaced by Calcium Carbonate (CaCO3) or Silica (SiO2)) — sedimentary

Fossilized Coral

Cnidaria (Anthozoa), often replaced by Calcium Carbonate (CaCO3) or Silica (SiO2)

Tumbled amber-colored pebble (Likely quartz/chert or iron-stained chalcedony; exact identification requires testing) — mineral

Tumbled amber-colored pebble

Likely quartz/chert or iron-stained chalcedony; exact identification requires testing

Chert (Flint) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (often called Jasper or Flint) (Silicon Dioxide (SiO2)) — sedimentary

Chert (often called Jasper or Flint)

Silicon Dioxide (SiO2)

Fossil-bearing sedimentary rock, possibly fossil wood or bone (Indeterminate silicified/carbonate fossil in sandstone or mudstone) — fossil

Fossil-bearing sedimentary rock, possibly fossil wood or bone

Indeterminate silicified/carbonate fossil in sandstone or mudstone

Chert (Jasper-like Silicate) (Microcrystalline quartz (SiO2)) — sedimentary

Chert (Jasper-like Silicate)

Microcrystalline quartz (SiO2)

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

Chert (Jasper/Flint variant)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Jasper (specifically a banded or dark variety) (Silicon Dioxide (SiO2) with impurities) — sedimentary

Jasper (specifically a banded or dark variety)

Silicon Dioxide (SiO2) with impurities

Moss Agate (Silicon Dioxide (SiO2) with Manganese or Iron Oxide inclusions) — mineral

Moss Agate

Silicon Dioxide (SiO2) with Manganese or Iron Oxide inclusions

Chert (often called Flint or Jasper) (Silicon Dioxide (SiO2)) — sedimentary

Chert (often called Flint or Jasper)

Silicon Dioxide (SiO2)

Chert (specifically Flint or Gray Chalcedony) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (specifically Flint or Gray Chalcedony)

Microcrystalline Quartz (SiO2)

Chert (variations include Flint/Novaculite) (Chert (formula: SiO2)) — sedimentary

Chert (variations include Flint/Novaculite)

Chert (formula: SiO2)