Chert (Flint)
Cryptocrystalline Quartz (SiO2)
sedimentary
Category
Sedimentary (Biogenic Sediment Or Biological Remain)
Browse sedimentary (biogenic sediment or biological remain) specimens identified by the Rock Identifier community.
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Chert (Black Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Jasper/Limonitic Chert)
Cryptocrystalline Quartz (SiO2) with Iron Oxide (FeO(OH)) inclusions
sedimentary
Quartz Geode (Druzy)
Crystalline Silicon Dioxide (SiO2)
mineral
Pyrite-bearing Rock
Iron Sulfide (FeS2)
mineral
Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Fossilized mammoth molar fragment
Proboscidean molar enamel and dentine, commonly Mammuthus spp.
fossil
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Chert (with Iron Staining)
Microcrystalline Quartz (SiO2)
sedimentary
Weathered fossiliferous limestone or fossil fragment
Indeterminate bioclastic carbonate rock; likely calcite (CaCO₃) with fossil shell material
fossil
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Polished fossil coral
Fossilized colonial coral, commonly tabulate or rugose coral; calcite (CaCO₃) replacement
fossil
Chert (Pink/Red variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Mother of Pearl (Nacre) / Shell Fragment
Biogenic Calcium Carbonate (Aragonite and Conchiolin)
fossil
Chalk
CaCO3 (primarily Calcium Carbonate), biogenic sedimentary rock
Sedimentary
Limestone with Fossil Impression
Calcium Carbonate (CaCO3)
sedimentary
Coquina / Fossiliferous Limestone
Fossiliferous Calcarenite (Calcium carbonate, CaCO3)
sedimentary
Limestone with Fossil inclusions
Fossiliferous Limestone (CaCO3)
sedimentary
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Fossilized bivalve shell fragment
Calcitic shell material, commonly Arca or related marine bivalve; primarily CaCO₃
fossil
Chert (containing Fossil Inclusions)
Microcrystalline Quartz (SiO2)
sedimentary
Fossiliferous Limestone (Crinoidal)
Crinoid Limestone (CaCO3 with fossil biological remains)
sedimentary
Quartz vein in weathered host rock
Quartz (SiO₂), likely in a weathered metamorphic or igneous matrix
mineral
Chert (and/or Chalcedony)
Silicon dioxide (SiO2)
sedimentary
Fossil Shark Tooth
Carcharocles or Lamniformes (order)
fossil
Pyrite
Iron Sulfide (FeS2)
mineral
Yellow Calcite
Calcium Carbonate (CaCO3)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Petrified wood
Silicified wood; commonly quartz (SiO₂) replacing wood tissue
fossil
Coquina
Bioclastic Limestone
sedimentary
Yellow Quartzite (River Pebble)
Metamorphic Quartzite (primarily SiO2)
metamorphic
Polished operculum (“Shiva eye” shell)
Calcium-carbonate shell operculum, commonly from a turban snail (family Turbinidae); not a mineral specimen
fossil
Chert (with Chalky Cortex)
Silicon Dioxide (SiO2)
sedimentary
Black flint (chert)
Microcrystalline quartz/chalcedony (SiO₂)
sedimentary
Limestone with Lichen/Algae
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Chert (Banded)
Chert (Microcrystalline Silicon Dioxide, SiO2)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Fossilized Shark Tooth
Fossil Chondrichthyes (various genera such as Carcharias or Odontaspis)
sedimentary