Limestone
Sedimentary Rock (Primarily Calcium Carbonate, CaCO3)
Category
Browse organic (non rock) specimens identified by the Rock Identifier community.
Limestone
Sedimentary Rock (Primarily Calcium Carbonate, CaCO3)
Fossilized Shell in Limestone
Carbonate sedimentary rock with Bivalvia or Brachiopoda remains
Laterite
Laterite (Iron and Aluminum-rich residual soil/rock)
Granite
Phaneritic Plutonic Felsic Rock (KAlSi3O8 - SiO2 - NaAlSi3O8)
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
Fossiliferous Limestone with Coral Imprint
Fossiliferous Limestone (CaCO3)
Fossiliferous Limestone (Crinoid stem)
CaCO3 (Calcium Carbonate) with Fossil Inclusions
Chert (and Flint)
Silicon Dioxide (SiO2)
Chert (with Quartz vein)
Chert (Silicon Dioxide, SiO2)
Chert (Quartz Variety)
Microcrystalline / Cryptocrystalline Quartz (SiO2)
Chert (Quartz Variety)
Chert (mostly SiO2 / Silicon Dioxide)
Chert (Iron-stained)
Chert (SiO2)
Chert with Quartz Veining
Silicon Dioxide (SiO2)
Ironstone Concretion / Goethite-Hematite Geode
Goethite / Hematite Concretion (Fe3O4 / FeO(OH) / Fe2O3)
Chert (Common Opal/Jasper variety)
Microcrystalline Quartz (SiO2) with hydration
Chert / River Jasper
Microcrystalline Quartz (SiO2)
Moss Agate
Silicon Dioxide with inclusions (SiO2 + Fe/Mn/Mg)
Obsidian
Volcanic glass (SiO2-rich extrusive igneous rock)
Chert (River Pebble)
Silicon Dioxide (SiO2)
Iron-rich quartzite or ironstone
Ferruginous quartzite; predominantly quartz (SiO₂) with hematite/goethite (Fe₂O₃/FeO(OH))
Chert Nodule
Microcrystalline Silica (SiO2)
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Sandstone Chert Concretion
Silica-cemented Concretion (primarily SiO2)
Petrified Wood
Silicified Wood (SiO2)
Fossil-bearing Sedimentary Rock
Sedimentum cum fossili
Chert (variously identified as Flint)
Microcrystalline Quartz (SiO2)
Opal
Hydrated amorphous silica (SiO2·nH2O)
Obsidian
Obsidian (Volcanic Glass; SiO2 content > 70%)
Limestone
Calcium Carbonate (CaCO3 - Calcite)
Concretionary Sandstone
Clastic Sedimentary Rock (Sandstone with secondary mineral cementation)
Pumice
Pumice (a volcanic glass, primarily SiO2 with Al2O3)
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
Chert (River Stone)
Silicon Dioxide (SiO2)
N/A (Non-Geological Specimen)
Obsidian
Volcanic Glass
Shale with Coprolite influence
Argillaceous sedimentary rock (Shale/Mudstone)
Limestone (Weathered Pebble)
Calcium Carbonate (CaCO3) / Limestone
Fossilized Shark Tooth
Chondrichthyes (Class)
Black Obsidian
Volcanic Glass (predominantly SiO2, Silicon Dioxide)
Quartzite
Metamorphosed Quartz Sandstone (SiO2)
Unidentified Dark Mineral or Rock
Indeterminate (Likely Silicon Dioxide or Carbon-based)
Sandstone with Trace Fossils
Quartz Arenite with Bioturbation (Trace Fossils)