Fossil Shell Fragment (possibly Brachiopod or Bivalve)
Calcium Carbonate (CaCO3) - Phylum Brachiopoda or Mollusca
sedimentary
Category
Sedimentary Or Igneous Fragment
Browse sedimentary or igneous fragment specimens identified by the Rock Identifier community.
Pyrite
Iron Sulfide (FeS2)
mineral
Agate (Geode nodule fragment)
Chalcedony (cryptocrystalline variety of Quartz), SiO2
mineral
Gneiss (Banded Gneiss)
Gneiss
metamorphic
Fossilized Megalodon Tooth Fragment
Otodus megalodon (Carcharocles megalodon fossil)
sedimentary
Quartz
Silicon Dioxide (SiO₂)
Mineral
Banded Gneiss
Gneiss (High-grade metamorphic rock typically composed of Quartz, Feldspar, and Mica)
metamorphic
Coquina
Coquina (Bioclastic Limestone)
sedimentary
Breccia
Clastic Breccia (General mineral composition depends on fragments, often SiO2 or CaCO3)
sedimentary
Fossiliferous Limestone
Fossiliferous Limestone (CaCO3)
sedimentary
Quartz (likely) or a Quartzite Pebble
Silicon dioxide (SiO2) for quartz. If it's quartzite, it's a metamorphic rock primarily composed of quartz.
Mineral, specifically a detrital grain
Quartz Geode/Druzy Quartz
Quartz (SiO₂)
Mineral
Sandstone (with potential fossil inclusions)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Conglomerate
Conglomerate (Clastic Sedimentary Rock)
Sedimentary
Sandstone (likely Greywacke or Siltstone variety)
Arenite / Siltstone (primarily SiO2)
sedimentary
Concrete with Aggregate
Composite construction material; primary matrix is Calcium Silicate Hydrate (C-S-H)
anthropogenic (human-made) sedimentary-like material
Fossiliferous Limestone (Coquina / Shell Conglomerate)
Bioclastic Limestone (composed primarily of CaCO3)
sedimentary
Pebble (likely a type of sandstone or quartzite pebble)
Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.
Sedimentary rock
Metal Chain (Likely Steel or a Steel Alloy)
Steel (primarily iron and carbon); specific alloy unknown
Man-made Object (Metal/Alloy)
Quartz Druzy (Geode Fragment)
Silicon Dioxide (SiO2)
mineral
Conglomerate
Conglomerate (Sedimentary rock)
sedimentary
Brecciated Chert
Brecciated Chert (Microcrystalline Quartz, SiO2)
sedimentary
Chert Breccia
Brecciated Microcrystalline Quartz (SiO2)
sedimentary
River Stone / Pebble
Clastic Sediment (composed largely of Quartz, Feldspar, and various rock fragments)
Mineral, Sediment
Quartz with mica and feldspar (Pegmatite fragment)
Granitic Pegmatite (composed mainly of SiO2 with KAlSi3O8)
igneous
Conglomerate
Conglomerate (SiO2, Al2O3, Fe2O3, CaCo3)
sedimentary
Asphalt (Bituminous pavement fragment)
Artificial conglomerate / Bitumen-Aggregate mixture
sedimentary
Fossiliferous Limestone (Shell Fragment)
Biogenic Limestone (Calcium Carbonate / CaCO3)
sedimentary
Fossilized Shark Tooth (Fragment)
Elasmobranchii fossil (likely Cretalamna or Squalicorax genus)
sedimentary
Quartz Druzy on Geode Fragment
Silicon Dioxide (SiO2)
mineral
Coquina
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Fossiliferous Limestone
Fossiliferous Calclutite / Bio-calcarenite (CaCO3)
sedimentary
Fossiliferous Limestone (Coquina / Shell Limestone)
Bioclastic Limestone (CaCO3)
sedimentary
Sandstone (lithic/greywacke variant)
Clastic sedimentary rock (primarily SiO2 with rock fragments)
sedimentary
Breccia
Breccia
sedimentary
Coquina
Biogenic Limestone (Calcitic shells)
sedimentary
Quartz Druzy Geode Fragment
Silicon Dioxide (SiO2)
mineral
Fossiliferous Limestone
Biogenic Calcium Carbonate (CaCO3)
sedimentary
Sedimentary Breccia
Clastic Breccia (CaCO3/SiO2 matrix)
sedimentary
Agate (or Banded Agate)
Agate (a variety of Chalcedony, which is a cryptocrystalline form of Quartz); Chemical Formula: SiO₂ (Silicon Dioxide)
Mineral, specifically a Cryptocrystalline Quartz variety
Breccia
Breccia (Clastic Sedimentary Rock)
sedimentary
Pyrite
Iron Disulfide (FeS2)
mineral