Agatized Petrified Wood
Silicon Dioxide (SiO2) - Chalcedony pseudomorph after Wood
Category
Browse organic (anthropogenic) specimens identified by the Rock Identifier community.
Agatized Petrified Wood
Silicon Dioxide (SiO2) - Chalcedony pseudomorph after Wood
Septarian Nodule
Calcite-bearing Septarian Concretion
Banded Chert
Microcrystalline Quartz (SiO2)
Chert (Black Chert / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert with Calcite Veins
Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3) intrusions
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
Fossiliferous Limestone (Coquina)
Biogenic Limestone (Calcium Carbonate, CaCO3)
Amber
Fossilized Tree Resin (Generic formula roughly C10H16O)
Amber
Fossilized Tree Resin (Succinite for Baltic varieties)
Chert (River Pebble)
Silicon Dioxide (SiO2)
Amber
Succinicum (Succinite); C10H16O
Travertine (Tufa)
Chemical Limestone (CaCO3)
Banded Agate (specifically Moss Agate or Plume Agate variety)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Coal
Bituminous Coal / Anthracite
Fossilized Shark Tooth (Fragment)
Elasmobranchii gen. indet.
Petrified Wood
Silicified wood (primarily SiO2)
Petrified Wood
Silicified wood (primarily Silicon Dioxide, SiO2)
Shale
Fissile mudrock (composed primarily of clay minerals and quartz)
Oak Wood (Wood Grain Pattern)
Quercus (genus)
Amber
Succinite (a fossilized organic resin containing succinic acid)
Chert
Chert (Silica: SiO2)
Fossil Coral
Scleractinia (Fossilized Coral) / Calcium Carbonate (CaCO3) or Silica (SiO2)
Fossil Coral (Honeycomb Coral)
Favosites (extinct genus of Tabulate coral)
Chert (Gravel pebble)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Quartzite
Quartzite (primarily SiO2)
Slate
Slate (foliated metamorphic rock, primarily composed of quartz, illite, chlorite, and micas)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Limestone
Calcium Carbonate (CaCO3)
Amber
Succinite (with formula approximately C10H16O)
Pearl
Organic gemstone (Calcium carbonate / CaCO3 + Conchiolin)
Fossiliferous limestone (likely ammonite/gastropod-bearing)
Bioclastic limestone; predominantly calcite (CaCO₃)
Fossil bivalve shell
Likely an extinct or modern-like ribbed cockle/scallop; exact genus requires locality and diagnostic hinge features
Calcite crystal
Calcite (calcium carbonate, CaCO₃)
Dyed Agate (Tumbled)
Silicon Dioxide (Chalcedony variety, artificially dyed)
Quartzite Pebble with Pyrite Coating
SiO2 (Quartz) with FeS2 (Pyrite) inclusions or surface coating
Amber
Fossilized Tree Resin (Successite)
Chert (Black Flint)
Microcrystalline Quartz (SiO2)
Fossiliferous Limestone
Limestone (CaCO3 - Calcium Carbonate)
Amber
Succinite (C10H16O)
Dendritic Agate (Tree Agate)
Chalcedony (Silicon Dioxide, SiO2) with Manganese or Iron Oxide inclusions
Amber
Succinite