Rock Identifier

Category

Organic (Geological Interest)

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

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

Petrified Wood

Silicified Wood (primarily SiO2)

Pyrite in Slate (Iron Sulfide (FeS2) in Slate host matrix) — metamorphic

Pyrite in Slate

Iron Sulfide (FeS2) in Slate host matrix

Tektite (likely Australite) (Tektite (no specific chemical formula as it's a natural glass of variable composition, mostly SiO2, Al2O3, FeO, MgO, CaO, K2O, Na2O, TiO2)) — Mineral (specifically a mineraloid)

Tektite (likely Australite)

Tektite (no specific chemical formula as it's a natural glass of variable composition, mostly SiO2, Al2O3, FeO, MgO, CaO, K2O, Na2O, TiO2)

Mineral (specifically a mineraloid)

Rounded brown chert (flint) pebble (Microcrystalline quartz (SiO₂), commonly with iron-oxide staining) — sedimentary

Rounded brown chert (flint) pebble

Microcrystalline quartz (SiO₂), commonly with iron-oxide staining

Tumbled moss agate (Chalcedony (microcrystalline quartz, SiO₂) with moss-like inclusions) — mineral

Tumbled moss agate

Chalcedony (microcrystalline quartz, SiO₂) with moss-like inclusions

Dendritic jasper/chalcedony (Silica-rich microcrystalline quartz (SiO₂) with manganese-oxide dendrites) — mineral

Dendritic jasper/chalcedony

Silica-rich microcrystalline quartz (SiO₂) with manganese-oxide dendrites

Banded agate (likely petrified wood or silicified sediment) (Microcrystalline quartz/chalcedony, SiO₂; possible silicified wood) — sedimentary

Banded agate (likely petrified wood or silicified sediment)

Microcrystalline quartz/chalcedony, SiO₂; possible silicified wood

Yellow calcite crystal specimen (Calcite (CaCO₃), likely honey/yellow calcite) — mineral

Yellow calcite crystal specimen

Calcite (CaCO₃), likely honey/yellow calcite

Botryoidal pyrite (likely with quartz or chlorite matrix) (Pyrite, FeS₂; botryoidal aggregate) — mineral

Botryoidal pyrite (likely with quartz or chlorite matrix)

Pyrite, FeS₂; botryoidal aggregate

Jasper (Silicon Dioxide (Microcrystalline Quartz, $SiO_2$)) — sedimentary

Jasper

Silicon Dioxide (Microcrystalline Quartz, $SiO_2$)

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

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (and/or Flint) (Microcrystalline or cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (and/or Flint)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (variant Flint) (Silicon Dioxide (SiO2)) — sedimentary

Chert (variant Flint)

Silicon Dioxide (SiO2)

Sandstone (Arenite (primarily composed of SiO2)) — sedimentary

Sandstone

Arenite (primarily composed of SiO2)

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

Chert (Red Jasper variant)

Microcrystalline Quartz (SiO2)

Chert (specifically Yellow/Brown Chert or Flint) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (specifically Yellow/Brown Chert or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Pyrite-bearing Schist (Pyritic Quartz-Mica Schist with FeS2 inclusion) — metamorphic

Pyrite-bearing Schist

Pyritic Quartz-Mica Schist with FeS2 inclusion

Chert (Jasper/Common Opal transition) (Microcrystalline Quartz (SiO2) with iron oxide inclusions) — sedimentary

Chert (Jasper/Common Opal transition)

Microcrystalline Quartz (SiO2) with iron oxide inclusions

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

Chert (Flint variety)

Chert (Microcrystalline or Cryptocrystalline Quartz), SiO2

Chert (varieties: Flint or Chalcedony) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (varieties: Flint or Chalcedony)

Microcrystalline Quartz (SiO2)

Glendonite (Calcite Pseudomorph after Ikaite) (Calcite (CaCO3) pseudomorph after Ikaite (CaCO3·6H2O)) — mineral

Glendonite (Calcite Pseudomorph after Ikaite)

Calcite (CaCO3) pseudomorph after Ikaite (CaCO3·6H2O)

Chert Nodule / Ironstone Concretion (Microcrystalline Quartz (SiO2) with Iron Oxides) — sedimentary

Chert Nodule / Ironstone Concretion

Microcrystalline Quartz (SiO2) with Iron Oxides

Petrified Wood (Silicon Dioxide (SiO2) permineralized organic matter) — sedimentary

Petrified Wood

Silicon Dioxide (SiO2) permineralized organic matter

Honey calcite (orange calcite) (Calcite, calcium carbonate (CaCO₃)) — mineral

Honey calcite (orange calcite)

Calcite, calcium carbonate (CaCO₃)

Yellow calcite crystal (Calcite (CaCO₃), likely honey/yellow calcite) — mineral

Yellow calcite crystal

Calcite (CaCO₃), likely honey/yellow calcite

Fine-grained brown sand or weathered soil (Unconsolidated siliciclastic sediment, likely quartz-rich sand (SiO₂) mixed with iron-oxide-coated grains) — sedimentary

Fine-grained brown sand or weathered soil

Unconsolidated siliciclastic sediment, likely quartz-rich sand (SiO₂) mixed with iron-oxide-coated grains

Coquina Limestone (Fossiliferous Limestone) (Calcareous bioclastic sedimentary rock (CaCO3)) — sedimentary

Coquina Limestone (Fossiliferous Limestone)

Calcareous bioclastic sedimentary rock (CaCO3)

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

Chert (Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint) (Chert (Silicon Dioxide, SiO2)) — sedimentary

Chert (Flint)

Chert (Silicon Dioxide, SiO2)

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

Chert (Nodule)

Silicon Dioxide (SiO2)

Chert (Yellow Jasper variant) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

Chert (Brown Variety) (Silicon dioxide (SiO2)) — sedimentary

Chert (Brown Variety)

Silicon dioxide (SiO2)

Chert (and its variety Flint) (Silicon Dioxide (SiO2) - Microcrystalline or cryptocrystalline Quartz) — sedimentary

Chert (and its variety Flint)

Silicon Dioxide (SiO2) - Microcrystalline or cryptocrystalline Quartz

Coquina / Fossiliferous Limestone (Coquina (composed primarily of Calcium Carbonate / CaCO3)) — sedimentary

Coquina / Fossiliferous Limestone

Coquina (composed primarily of Calcium Carbonate / CaCO3)

Chert (often called Flint when dark) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

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

Chert (Chert / Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (variations include Flint or Jasper) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (variations include Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone (Sandstone (Quartz-rich Arenite / SiO2)) — sedimentary

Sandstone

Sandstone (Quartz-rich Arenite / SiO2)

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Chert (likely flint), possibly chalcedony-rich (Microcrystalline quartz, SiO₂ (quartz/chalcedony)) — sedimentary

Chert (likely flint), possibly chalcedony-rich

Microcrystalline quartz, SiO₂ (quartz/chalcedony)

Ironstone Concretion (Ironstone (Siderite/Goethite/Hematite matrix)) — sedimentary

Ironstone Concretion

Ironstone (Siderite/Goethite/Hematite matrix)