Rock Identifier

Category

Man Made Object (Coin)

Browse man made object (coin) specimens identified by the Rock Identifier community.

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

Sandstone (with Lichen)

Arenite (composed primarily of SiO2)

Flint (Chert (a form of cryptocrystalline quartz, chemical formula SiO₂)) — Mineral

Flint

Chert (a form of cryptocrystalline quartz, chemical formula SiO₂)

Banded Gneiss (Gneiss (Metamorphic high-grade rock)) — metamorphic

Banded Gneiss

Gneiss (Metamorphic high-grade rock)

Gneiss (Gneiss (High-grade regional metamorphic rock)) — metamorphic

Gneiss

Gneiss (High-grade regional metamorphic rock)

Quartz (Quartzite) (Silicon Dioxide (SiO2)) — metamorphic

Quartz (Quartzite)

Silicon Dioxide (SiO2)

Quartzite (specifically a river-worn pebble) (Quartzite (primarily SiO2)) — metamorphic

Quartzite (specifically a river-worn pebble)

Quartzite (primarily SiO2)

Red Sandstone (Clastic Terrigenous Sedimentary Rock (typically Hematitic Quartz Arenite or Arkose)) — sedimentary

Red Sandstone

Clastic Terrigenous Sedimentary Rock (typically Hematitic Quartz Arenite or Arkose)

Obsidian (Volcanic Glass (SiO2 + impurities)) — igneous

Obsidian

Volcanic Glass (SiO2 + impurities)

Fossiliferous Limestone (with Crinoids/Coral) (Fossiliferous Limestone (CaCO3)) — sedimentary

Fossiliferous Limestone (with Crinoids/Coral)

Fossiliferous Limestone (CaCO3)

Banded Sandstone (Liesegang Rings) (Sedimentary sandstone with Iron oxide precipitates) — sedimentary

Banded Sandstone (Liesegang Rings)

Sedimentary sandstone with Iron oxide precipitates

Clear Quartz (Rock Crystal) (Silicon Dioxide (SiO2)) — mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

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

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Ironstone (Limonitic Concretion) (Limonite (FeO(OH)·nH2O) with Goethite and Hematite inclusions) — sedimentary

Ironstone (Limonitic Concretion)

Limonite (FeO(OH)·nH2O) with Goethite and Hematite inclusions

Fluorite with Rhodochrosite (Fluorite (CaF2) and Rhodochrosite (MnCO3)) — Mineral

Fluorite with Rhodochrosite

Fluorite (CaF2) and Rhodochrosite (MnCO3)

Agate (Silicon Dioxide (SiO2)) — mineral

Agate

Silicon Dioxide (SiO2)

Coral Fossil (Petrified Coral) (Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)) — sedimentary

Coral Fossil (Petrified Coral)

Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)

Greenstone (Greenschist (containing chlorite, epidote, and actinolite)) — metamorphic

Greenstone

Greenschist (containing chlorite, epidote, and actinolite)

Kambaba Jasper (Crocodile Jasper) (Rhyolite containing Fossilized Cyanobacteria (Stromatolite)) — sedimentary

Kambaba Jasper (Crocodile Jasper)

Rhyolite containing Fossilized Cyanobacteria (Stromatolite)

Milky Quartz (Quartz (Silicon Dioxide, SiO2)) — mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Red Jasper (possibly Carnelian) (Silicon Dioxide (SiO2) with Hematite impurities) — mineral

Red Jasper (possibly Carnelian)

Silicon Dioxide (SiO2) with Hematite impurities

Milky Quartz (Silicon Dioxide (SiO2)) — mineral

Milky Quartz

Silicon Dioxide (SiO2)

Limonite (Iron-rich Siltstone / Sandstone base) (Hydrous ferric oxide mixture (FeO(OH)·nH2O)) — sedimentary

Limonite (Iron-rich Siltstone / Sandstone base)

Hydrous ferric oxide mixture (FeO(OH)·nH2O)

Limonite (Iron Ore) (Limonite (Hydrous iron(III) oxide-hydroxide mixture, primarily FeO(OH)·nH2O)) — mineral

Limonite (Iron Ore)

Limonite (Hydrous iron(III) oxide-hydroxide mixture, primarily FeO(OH)·nH2O)

Jasper (Jasper (Silicon Dioxide, SiO2)) — sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

Quartzite (Quartzite (primarily SiO2)) — metamorphic

Quartzite

Quartzite (primarily SiO2)

Limonite (Iron Ore) (Limonite (FeO(OH)·nH2O)) — mineral

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Chalcedony Nodule (Carnelian/Agate) (Chalcedony (Silicon Dioxide, SiO2)) — mineral

Chalcedony Nodule (Carnelian/Agate)

Chalcedony (Silicon Dioxide, SiO2)

Sandstone (Calcareous or Ferruginous) (Clastic sedimentary rock (SiO2 with CaCO3 or Fe2O3 cement)) — sedimentary

Sandstone (Calcareous or Ferruginous)

Clastic sedimentary rock (SiO2 with CaCO3 or Fe2O3 cement)

Serpentine (Serpentine-group (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4) — metamorphic

Serpentine

Serpentine-group (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4

Quartz (Silicon Dioxide (SiO2)) — Mineral

Quartz

Silicon Dioxide (SiO2)

Sandstone (likely Quartz Sandstone) (Arenite (SiO2 based)) — sedimentary

Sandstone (likely Quartz Sandstone)

Arenite (SiO2 based)

Basalt with Iron Oxidation (Amygdaloidal Basalt (silicate rock primarily plagioclase, pyroxene, and olivine)) — igneous

Basalt with Iron Oxidation

Amygdaloidal Basalt (silicate rock primarily plagioclase, pyroxene, and olivine)

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Basalt (Polished River Stone) (Basalt (Extrusive Mafic Volcanic Rock)) — igneous

Basalt (Polished River Stone)

Basalt (Extrusive Mafic Volcanic Rock)

Hematite (Hematite (Fe2O3)) — mineral

Hematite

Hematite (Fe2O3)

Obsidian (Apache Tear) (Amorphous Volcanic Glass (SiO2 + impurities)) — igneous

Obsidian (Apache Tear)

Amorphous Volcanic Glass (SiO2 + impurities)

River Cobble (Quartzite) (Meta-orthoquartzite) — metamorphic

River Cobble (Quartzite)

Meta-orthoquartzite

Fluorite (Durango Fluorite) (Calcium Fluoride (CaF2)) — mineral

Fluorite (Durango Fluorite)

Calcium Fluoride (CaF2)

Amygdaloidal Basalt (Amygdaloidal Basalt (Ca-rich Plagioclase, Pyroxene, and Olivine)) — igneous

Amygdaloidal Basalt

Amygdaloidal Basalt (Ca-rich Plagioclase, Pyroxene, and Olivine)

Sodalite (Sodalite (Na8(Al6Si6O24)Cl2)) — mineral

Sodalite

Sodalite (Na8(Al6Si6O24)Cl2)

Agate (Silicon Dioxide (SiO2)) — mineral

Agate

Silicon Dioxide (SiO2)

Gold Nugget (Native Gold (Au)) — mineral

Gold Nugget

Native Gold (Au)