Rock Identifier

Category

Organic (Non Geological)

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

Orange Calcite (Calcium Carbonate (CaCO3)) — mineral

Orange Calcite

Calcium Carbonate (CaCO3)

Concretion or weathered iron-rich nodule (Likely an ironstone/siderite–goethite concretion; exact identification requires testing) — sedimentary

Concretion or weathered iron-rich nodule

Likely an ironstone/siderite–goethite concretion; exact identification requires testing

Limestone (or Sandstone) (Calcium Carbonate (CaCO3) / Silica (SiO2)) — sedimentary

Limestone (or Sandstone)

Calcium Carbonate (CaCO3) / Silica (SiO2)

Ironstone Concretion / Limonite Node (Goethite and Limonite (FeO(OH) nH2O)) — sedimentary

Ironstone Concretion / Limonite Node

Goethite and Limonite (FeO(OH) nH2O)

Pearl (Aragonite / Calcium Carbonate (CaCO3)) — mineral

Pearl

Aragonite / Calcium Carbonate (CaCO3)

Asphalt (Aggregate) (Bituminous macadam / Concrete Aggregate) — sedimentary

Asphalt (Aggregate)

Bituminous macadam / Concrete Aggregate

Petrified Wood (Silicified Wood (SiO2)) — metamorphic

Petrified Wood

Silicified Wood (SiO2)

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

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Moss Agate (Chalcedony (Silicon Dioxide, SiO2) with inclusions) — mineral

Moss Agate

Chalcedony (Silicon Dioxide, SiO2) with inclusions

Limestone (Sedimentary Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Sedimentary Calcium Carbonate (CaCO3)

Glauconitic Sandstone (Greensand) (Glauconitic quartz wacke or arenite) — sedimentary

Glauconitic Sandstone (Greensand)

Glauconitic quartz wacke or arenite

Greenschist (likely chlorite schist) (Greenschist-facies metamorphic rock; commonly quartz + chlorite ± actinolite, epidote, albite, and mica) — metamorphic

Greenschist (likely chlorite schist)

Greenschist-facies metamorphic rock; commonly quartz + chlorite ± actinolite, epidote, albite, and mica

Limonite Pseudomorph after Pyrite (Limonite (Hydrous iron oxides, FeO(OH)·nH2O) replacing Pyrite (FeS2)) — mineral

Limonite Pseudomorph after Pyrite

Limonite (Hydrous iron oxides, FeO(OH)·nH2O) replacing Pyrite (FeS2)

Quartzite (Quartzite (SiO2)) — metamorphic

Quartzite

Quartzite (SiO2)

Obsidian (Volcanic Glass (mostly SiO2)) — igneous

Obsidian

Volcanic Glass (mostly SiO2)

Obsidian (Volcanic glass (SiO2 - Silicon Dioxide with impurities)) — Igneous

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Coal (most likely Bituminous or Anthracite) (Coal (organic sedimentary rock)) — Sedimentary

Coal (most likely Bituminous or Anthracite)

Coal (organic sedimentary rock)

Petrified Wood (Silicified Wood (SiO2)) — mineral

Petrified Wood

Silicified Wood (SiO2)

Fossilized Fish Skeleton in Matrix (Vertebrata (Class: Actinopterygii), typically found in limestone or shale matrices) — sedimentary

Fossilized Fish Skeleton in Matrix

Vertebrata (Class: Actinopterygii), typically found in limestone or shale matrices

Geode with Quartz Crystal Cavity (Silicon Dioxide (SiO2) in Calcareous/Siliceous Matrix) — sedimentary

Geode with Quartz Crystal Cavity

Silicon Dioxide (SiO2) in Calcareous/Siliceous Matrix

Marble (Recrystallized Calcite (CaCO3)) — metamorphic

Marble

Recrystallized Calcite (CaCO3)

Malachite (Copper carbonate hydroxide [Cu2CO3(OH)2]) — mineral

Malachite

Copper carbonate hydroxide [Cu2CO3(OH)2]

Anthracite Coal (Anthracite (Carbon Content: 86%-97%)) — metamorphic

Anthracite Coal

Anthracite (Carbon Content: 86%-97%)

Limestone Concretion (Botryoidal/Calcareous Nodules) (Calcium Carbonate Concretion (CaCO3)) — sedimentary

Limestone Concretion (Botryoidal/Calcareous Nodules)

Calcium Carbonate Concretion (CaCO3)

Glauconitic Sandstone (Glauconitic Quartz Arenite) — sedimentary

Glauconitic Sandstone

Glauconitic Quartz Arenite

Raw turquoise (Turquoise — hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O) — mineral

Raw turquoise

Turquoise — hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O

Septarian Nodule (Micro-fragment) (Septarian Nodule / Concretion (CaCO3 + CaMg(CO3)2 + Quartz)) — sedimentary

Septarian Nodule (Micro-fragment)

Septarian Nodule / Concretion (CaCO3 + CaMg(CO3)2 + Quartz)

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

Petrified Wood

Silicified Wood (primarily SiO2)

Banded Chert with Quartz Veining (Microcrystalline Quartz (SiO2)) — sedimentary

Banded Chert with Quartz Veining

Microcrystalline Quartz (SiO2)

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

Pyrite in Slate

Iron Sulfide (FeS2) in Slate host matrix

Baroque Pearl (and potentially a small Sapphire/Blue Topaz) (Pearl: Calcium Carbonate (aragonite or calcite) with conchiolin. Sapphire: Aluminum Oxide (Al2O3). Blue Topaz: Al2SiO4(F,OH)2.) — Organic Gemstone (for pearl), Mineral (for sapphire/topaz)

Baroque Pearl (and potentially a small Sapphire/Blue Topaz)

Pearl: Calcium Carbonate (aragonite or calcite) with conchiolin. Sapphire: Aluminum Oxide (Al2O3). Blue Topaz: Al2SiO4(F,OH)2.

Organic Gemstone (for pearl), Mineral (for sapphire/topaz)

Pearl (Nacre (aragonite, CaCO₃, in a conchiolin matrix)) — gemstone

Pearl

Nacre (aragonite, CaCO₃, in a conchiolin matrix)

Weathered iron-rich river pebble (Ferruginous chert or ironstone pebble; exact identification requires testing) — sedimentary

Weathered iron-rich river pebble

Ferruginous chert or ironstone pebble; exact identification requires testing

Weathered iron-rich river pebble (Ferruginous chert or ironstone (hematite/goethite-bearing silica-rich rock)) — sedimentary

Weathered iron-rich river pebble

Ferruginous chert or ironstone (hematite/goethite-bearing silica-rich rock)

Common Opal (Green Opal / Pistachio Opal) (Hydrated silica (SiO2·nH2O)) — mineraloid

Common Opal (Green Opal / Pistachio Opal)

Hydrated silica (SiO2·nH2O)

Porous limestone (likely reef or shell limestone) (Calcium-carbonate rock, predominantly calcite (CaCO₃); possibly bioclastic limestone or coquina) — sedimentary

Porous limestone (likely reef or shell limestone)

Calcium-carbonate rock, predominantly calcite (CaCO₃); possibly bioclastic limestone or coquina

Siltstone (Siltstone) — sedimentary

Siltstone

Siltstone

Blue sapphire ring (Corundum, Al₂O₃; blue color typically from trace iron and titanium) — gemstone

Blue sapphire ring

Corundum, Al₂O₃; blue color typically from trace iron and titanium

Quartzite (Metamorphic Quartzite (SiO2)) — metamorphic

Quartzite

Metamorphic Quartzite (SiO2)

Wonderstone (Liesegang Sandstone) (Silicified Sandstone with Liesegang Rings (SiO2 + FeO(OH))) — sedimentary

Wonderstone (Liesegang Sandstone)

Silicified Sandstone with Liesegang Rings (SiO2 + FeO(OH))

Obsidian (Volcanic glass (mainly SiO2)) — Igneous

Obsidian

Volcanic glass (mainly SiO2)