Rock Identifier

Category

Organic Crystal (Mineraloid)

Browse organic crystal (mineraloid) specimens identified by the Rock Identifier community.

Shark Tooth Fossil (Carcharhiniformes or Lamniformes (order level fossil)) — fossil

Shark Tooth Fossil

Carcharhiniformes or Lamniformes (order level fossil)

Calligraphy Stone (Fossiliferous Limestone (containing Hematite and Shells)) — sedimentary

Calligraphy Stone

Fossiliferous Limestone (containing Hematite and Shells)

Black Limestone with Calcite Veins (Limestone (Calcium Carbonate, CaCO3)) — sedimentary

Black Limestone with Calcite Veins

Limestone (Calcium Carbonate, CaCO3)

Pearl necklace (Pearl (biogenic calcium carbonate, chiefly aragonite; CaCO₃)) — gemstone

Pearl necklace

Pearl (biogenic calcium carbonate, chiefly aragonite; CaCO₃)

Amber (Succinite (Resinite)) — fossil

Amber

Succinite (Resinite)

Chert / Chalcedony (Silicon Dioxide (SiO2)) — sedimentary

Chert / Chalcedony

Silicon Dioxide (SiO2)

Banded calcite (travertine or calcite-rich carbonate) (Calcite, CaCO₃; likely banded travertine or recrystallized limestone) — sedimentary

Banded calcite (travertine or calcite-rich carbonate)

Calcite, CaCO₃; likely banded travertine or recrystallized limestone

Fossiliferous Limestone (Sedimentary Calcium Carbonate (CaCO3)) — sedimentary

Fossiliferous Limestone

Sedimentary Calcium Carbonate (CaCO3)

Fossilized Shell (Invertebrate fossil (Bivalvia or Brachiopoda)) — fossil

Fossilized Shell

Invertebrate fossil (Bivalvia or Brachiopoda)

Tumbled amber (Amber (fossilized plant resin; commonly succinite, C10H16O)) — gemstone

Tumbled amber

Amber (fossilized plant resin; commonly succinite, C10H16O)

Fossiliferous Limestone with Rugose Coral (Calcium Carbonate (CaCO3) featuring Rugosa (extinct order of solitary and colony corals)) — sedimentary

Fossiliferous Limestone with Rugose Coral

Calcium Carbonate (CaCO3) featuring Rugosa (extinct order of solitary and colony corals)

Coal (Anthracite / Bituminous Coal) — sedimentary

Coal

Anthracite / Bituminous Coal

Limestone / Dolomite (Calcium Carbonate (CaCO3) / Calcium Magnesium Carbonate (CaMg(CO3)2)) — sedimentary

Limestone / Dolomite

Calcium Carbonate (CaCO3) / Calcium Magnesium Carbonate (CaMg(CO3)2)

Chalk (CaCO3 (primarily Calcium Carbonate), biogenic sedimentary rock) — Sedimentary

Chalk

CaCO3 (primarily Calcium Carbonate), biogenic sedimentary rock

Green Moss Agate / Jasper (Silicon Dioxide (SiO2) - Microcrystalline Quartz with Iron and Manganese inclusions) — sedimentary

Green Moss Agate / Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz with Iron and Manganese inclusions

Limestone with Lichen (Calcium Carbonate (CaCO3) with Endolithic/Epilithic Lichen) — sedimentary

Limestone with Lichen

Calcium Carbonate (CaCO3) with Endolithic/Epilithic Lichen

Red Jasper (possibly Petrified Wood) (Silicon Dioxide (SiO2) with Hematite inclusions) — sedimentary (secondary formation)

Red Jasper (possibly Petrified Wood)

Silicon Dioxide (SiO2) with Hematite inclusions

sedimentary (secondary formation)

Amber (Fossilized Tree Resin (C10H16O)) — gemstone

Amber

Fossilized Tree Resin (C10H16O)

Limestone (Calcium Carbonate (CaCO3)) — sedimentary

Limestone

Calcium Carbonate (CaCO3)

Chert (often associated with Jasper) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (often associated with Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Granite (Granite (a plutonic igneous rock)) — Igneous

Granite

Granite (a plutonic igneous rock)

Slag (Industrial Glass Slag) (Amorphous Silicate Glass (often containing Al, Ca, Mg, and Ti oxides)) — Mineraloid (Industrial byproduct)

Slag (Industrial Glass Slag)

Amorphous Silicate Glass (often containing Al, Ca, Mg, and Ti oxides)

Mineraloid (Industrial byproduct)

Amber (Succinite (Fossilized Resin)) — gemstone

Amber

Succinite (Fossilized Resin)

Cobalt Blue Sea Glass (Amorphous Silica Glass (SiO2 + CoO)) — mineraloid / anthropogenic material

Cobalt Blue Sea Glass

Amorphous Silica Glass (SiO2 + CoO)

mineraloid / anthropogenic material

Anthracite Coal (Anthracite) — sedimentary

Anthracite Coal

Anthracite

Chert (River Cobble) (Microcrystalline or cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (River Cobble)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Granite (Granite) — igneous

Granite

Granite

Granite (Granite (a plutonic igneous rock composed of quartz, feldspar, and mica)) — igneous

Granite

Granite (a plutonic igneous rock composed of quartz, feldspar, and mica)

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

Chert (and/or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Anthracite Coal (Anthracite) — metamorphic

Anthracite Coal

Anthracite

Slag (Industrial Glass/Metal Waste) (Artificial silicate/ferro-silicate byproduct) — Mineraloid (Industrial byproduct)

Slag (Industrial Glass/Metal Waste)

Artificial silicate/ferro-silicate byproduct

Mineraloid (Industrial byproduct)

Anthracite Coal (Anthracite (Highly Metamorphosed Coal)) — sedimentary

Anthracite Coal

Anthracite (Highly Metamorphosed Coal)

Anthracite Coal (Anthracite) — metamorphic

Anthracite Coal

Anthracite

Cullet Glass (sometimes mistaken for Blue Obsidian or Slag) (Amorphous Silicon Dioxide (SiO2) with chemical additives (e.g., Cobalt for blue color)) — mineraloid / industrial byproduct

Cullet Glass (sometimes mistaken for Blue Obsidian or Slag)

Amorphous Silicon Dioxide (SiO2) with chemical additives (e.g., Cobalt for blue color)

mineraloid / industrial byproduct

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

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Red Slag Glass (Amorphous Silica (Industrial byproduct with metallic oxide dopants)) — Mineraloid / Industrial Byproduct

Red Slag Glass

Amorphous Silica (Industrial byproduct with metallic oxide dopants)

Mineraloid / Industrial Byproduct

Septarian Nodule or Mud Crack Fossil (Septarian Nodule (Concretion)) — sedimentary

Septarian Nodule or Mud Crack Fossil

Septarian Nodule (Concretion)

Fossiliferous Limestone (Calcium Carbonate (CaCO3) - Limestone) — sedimentary

Fossiliferous Limestone

Calcium Carbonate (CaCO3) - Limestone

Chert (and Limestone) (Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3)) — sedimentary

Chert (and Limestone)

Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3)

Chert (with Iron Staining) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (with Iron Staining)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Limestone (Calcium Carbonate (CaCO3 - Calcite)) — sedimentary

Limestone

Calcium Carbonate (CaCO3 - Calcite)

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

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)