Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Category
Organic (Geological Interest)
Browse organic (geological interest) specimens identified by the Rock Identifier community.
Chert with Limestone matrix
Microcrystalline silica (SiO2) in Calcite (CaCO3) matrix
sedimentary
Rounded quartz-rich pebble
Likely granitoid-derived quartz–feldspar cobble; exact identification requires testing
igneous
Likely bituminous coal
Coal, predominantly carbon-rich organic matter with variable maceral and mineral content
sedimentary
Grass (Organic Matter/Soil)
Poaceae (family of monocotyledonous flowering plants)
Organic Materia (Not a rock or mineral)
Chert (Flint variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Jasper
Silicon Dioxide (Microcrystalline Quartz, SiO2)
sedimentary
Jasper
Silicon dioxide (SiO2)
sedimentary
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Limestone with Calcite Veins
Calcite-veined Argillaceous Limestone
sedimentary
Fossiliferous Rock (Invertebrate Fossil in Matrix)
Fossiliferous limestone or shaly matrix containing skeletal fossil remains
fossil
Iron-rich quartzite or weathered ironstone pebble
Quartzite, chiefly SiO₂, with iron-oxide minerals (hematite/goethite)
metamorphic
Pink Coral
Corallium rubrum (or related species, composed of calcium carbonate)
gemstone
Petrified Wood
Silicified wood (SiO2)
fossil
Fossiliferous Kalkstein (Marl/Sandstone)
Fossiliferous calcarenite/siltstone
sedimentary
Fossilized Horn Coral
Order Rugosa (Rugose Coral)
sedimentary
Moss Agate
Silicon Dioxide with inclusions (SiO2 + Fe/Mn/Mg)
mineral
Weathered iron-rich concretion or lateritic pebble
Goethite/hematite-bearing ferruginous concretion; composition uncertain from image
sedimentary
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Chert / Jasper
Cryptocrystalline Silica (SiO2)
sedimentary
Chert (Flint)
Microcrystalline Quartz or Cryptocrystalline Silica (SiO2)
sedimentary
Chert (Flint)
Microcrystalline Silicon Dioxide (SiO2)
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Flint variety)
Silicon Dioxide (SiO2)
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Chert (Light Variety)
Sedimentary cryptocrystalline quartz (SiO2)
sedimentary
Fossiliferous Limestone
Calcite (CaCO3) with Bioclastic inclusions
sedimentary
Chert / Flint
Chert (Cryptocrystalline Quartz, SiO2)
sedimentary
Chert (Yellow Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Black Jasper
Silicon Dioxide (SiO2) with impurities
sedimentary
Sea Shell (Mollusk Shell)
Calcium Carbonate (Aragonite/Calcite)
fossil
Concretion
Septarian Concretion (Fragmentary)
sedimentary
Weathered iron-rich concretion or possible meteorite
Likely limonite/goethite concretion; meteorite status unconfirmed
mineral
Unknown Organic Object (likely a berry or fruit)
Not applicable; this is not a geological specimen. If it were a cranberry, its scientific name would be Vaccinium macrocarpon; if a cherry, it would be Prunus avium or Prunus cerasus.
Organic Material (likely a fruit or berry)
Fossil Coral
Cnidaria Anthozoa (Fossilized)
sedimentary
Seashell (Cone Snail Shell)
Conus sp. (Calcium Carbonate, CaCO3)
fossil
Seashell Fossil
Gastropoda fossil
fossil
Vesicular basalt (likely scoria)
Basaltic volcanic rock; primarily plagioclase, pyroxene, and olivine, with abundant gas vesicles
igneous
Siltstone with Fossil Cast
Sedimentary Rock (Siltstone / Fine-grained Sandstone)
sedimentary
Carved pyrite frog or toad
Pyrite (iron disulfide, FeS₂), likely a carved massive aggregate
mineral