Unidentified Dark Mineral or Rock
Indeterminate (Likely Silicon Dioxide or Carbon-based)
Category
Browse organic structure (not a rock) specimens identified by the Rock Identifier community.
Unidentified Dark Mineral or Rock
Indeterminate (Likely Silicon Dioxide or Carbon-based)
Limestone
Calcium Carbonate (CaCO3)
Fossiliferous Limestone
Sedimentary Calcium Carbonate (CaCO3)
Pyrite in Slate
Iron Sulfide (FeS2) in Slate host matrix
Fossiliferous Siltstone
Clastic Sedimentary Rock with Fossil Inclusions
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
Dendritic jasper/chalcedony
Silica-rich microcrystalline quartz (SiO₂) with manganese-oxide dendrites
Chert (Pebble)
Microcrystalline Quartz (SiO2)
Fossilized Bivalve Shell (Fossilized Clam)
Bivalvia (class) / CaCO3 (Calcium Carbonate)
Fossiliferous Limestone
Calcite-rich Sedimentary Rock (CaCO3)
Tumbled banded agate (likely chalcedony)
Microcrystalline quartz, SiO₂; probable banded chalcedony/agate
Chert
Cryptocrystalline Quartz (SiO2)
Chert (Nodule)
Microcrystalline Quartz (SiO2)
Amber
Succinite (with empirical formula approximately C10H16O)
Amber
Succinite
Limestone Pebble
Calcite-rich Sedimentary Rock (CaCO3)
Chert (Quartz Variety)
Microcrystalline / Cryptocrystalline Quartz (SiO2)
Travertine / Tufa
Calcium Carbonate (CaCO3)
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
Chert (and/or River Pebble)
Microcrystalline silica (SiO2)
Red Coral
Corallium rubrum
Tree Agate
Silicon Dioxide (SiO2) with Dendritic Inclusions
Chert (Flint)
Silicon Dioxide (SiO2)
Graphite-bearing schist (probable)
Graphite schist; chiefly quartz, mica, and graphite
Fossilized Coprolite
Coprolite (fossilized feces)
Fossilized tooth, likely shark tooth
Fossilized selachian tooth; possibly a worn Otodus or related shark tooth
Chert (Jasper)
Sedimentary Cryptocrystalline Quartz (SiO2)
Amber (fossilized tree resin)
Succinite; organic resin composed mainly of polymerized terpenoids
Sandstone (likely Arkose or Quartz Sandstone)
Arenite (SiO2 principal component)
Petrified Wood
Silicified Wood (SiO2)
Chert with Quartz Veining
Silicon Dioxide (SiO2)
River Stone (likely Mudstone or Siltstone)
Lutite (Clastic sedimentary rock composed of clay and silt-sized particles)
Limestone (River Pebble)
Calcium Carbonate (CaCO3)
Amber
Succinite (organic hydrocarbon)
Moss Agate
Silicon Dioxide (SiO2) with inclusions
Chert (with Quartz vein)
Chert (Silicon Dioxide, SiO2)
Shale with Coprolite influence
Argillaceous sedimentary rock (Shale/Mudstone)
Chert (River Stone)
Silicon Dioxide (SiO2)
Jasper
Jasper (Cryptocrystalline variety of Quartz, SiO2)
Chert / River Jasper
Microcrystalline Quartz (SiO2)
Chert (often called Jasper or Flint)
Microcrystalline Quartz (SiO2)
Glauconitic Sandstone (Greensand)
Glauconitic Quartz Arenite (containing Glauconite, (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2)