Anthracite Coal
Carbon (with trace impurities)
Category
Browse organic (pseudo geological) specimens identified by the Rock Identifier community.
Anthracite Coal
Carbon (with trace impurities)
Limestone
Calcium carbonate rock (predominantly Calcite, CaCO3)
Petrified Wood
Silicified Wood (primarily Silicon Dioxide, SiO2)
Pitted Limestone
Calcium Carbonate (CaCO3)
Quartz (Chert/Chalcedony variety)
Silicon Dioxide (SiO2)
Lemon (Mock specimen mimicking Citrine/Sulfur)
Citrus x limon
Chert (Nodule)
Chert (Cryptocrystalline Silica, SiO2)
Fossilized Brain Coral
Diploria labyrinthiformis (Fossilized)
Fossil Coral (Rugosa or Solitary Coral)
Rugosa (Order), often referred to as 'Horn Coral' (Lithostrotionella or Grewingkia)
Fossiliferous Limestone (with Crinoids)
CaCO3 (Calcium Carbonate)
Petrified Wood
Silicified wood (primarily SiO2)
Fossiliferous Limestone
Fossiliferous Limestone (CaCO3 with organic inclusions)
Flint / Chert Nodule
Microcrystalline quartz (SiO2)
Moqui Marble (Shaman Stone)
Ironstone Concretion (Goethite/Hematite Shell)
Petrified Wood / Jasper Chert
Silicified Wood / Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified wood (primarily Silicon Dioxide, SiO2)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Pyrite Concretion
Iron Sulfide (FeS2) in Sedimentary Matrix
Petrified Wood
Silicified Wood (primarily SiO2)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Petrified Wood
Silicified Wood (SiO2)
Agatized Petrified Wood
Silicon Dioxide (SiO2) - Chalcedony pseudomorph after Wood
Fossiliferous Limestone with Brachiopod shell
Calcium carbonate (CaCO3)
Gastropod Fossil (Snail Steinkern)
Class Gastropoda (internal mold)
Petrified Wood
Silicified Wood (SiO2)
Fossiliferous Chert (with Fossil Shells)
Silicon Dioxide (SiO2) with biogenic inclusions
Chert (likely brown flint)
Microcrystalline quartz, SiO₂ (chalcedonic quartz aggregate)
Fossilized Vertebra
Chordata fossil (Vertebra)
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement of Cellulose)
Oak-grain Laminate (Industrial/Decorative Furniture Finish)
Melamine Resin-impregnated Decorative Paper on Particleboard (Cellulose/Thermosetting Plastic)
Amber
Succinite (C10H16O)
Amber (Green variation)
Succinite
Likely bituminous coal
Coal, predominantly maceral-rich carbonaceous material (composition varies)
Limestone
Calcareous sedimentary rock (CaCO3)
Chert (Jasper)
Silicon Dioxide (SiO2)
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Chert (and Jasper blend)
Chert (Microcrystalline Quartz, SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Chert / Flint
Microcrystalline or Cryptocrystalline Quartz (SiO2)