Likely weathered limestone or calcitic marble
Calcite (CaCO₃), probably micritic limestone; marble is a possible metamorphic alternative
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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Oyster shell fragment
Ostreidae shell; primarily calcite (CaCO₃)
fossil
Shale
Argillite / Shaly Mudstone
sedimentary
Shale
Lutaceous sedimentary rock
sedimentary
Chert Pebble (with Quartz Vein)
Chert (Cryptocrystalline Silica - SiO2)
sedimentary
Porous limestone (likely fossiliferous or reef limestone)
Calcite-rich carbonate rock; predominantly CaCO₃
sedimentary
Orbicular Jasper (Eye Jasper / Kambaba-like pattern)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Amber / Copal
Fossilized Tree Resin (Succinate)
Mineraloid
Petrified Wood
Silicified Wood (SiO2)
fossil
Amber
Fossilized tree resin; commonly derived from ancient conifers
fossil
Shark Tooth Fossil
Otodus obliquus (or similar prehistoric lamniform shark tooth)
fossil
Quartz Sand/Gravel
Silicon Dioxide (SiO2)
sedimentary
Fossil Shark Tooth (embedded in matrix)
Lamniformes (likely Cretalamna or Squalicorax) within phosphatic/calcareous matrix
sedimentary
Layered sandstone and shale outcrop
Clastic sedimentary strata, likely sandstone interbedded with mudstone/shale
sedimentary
Pearl-bearing oyster shell
Nacreous shell, primarily aragonite (CaCO₃), with natural pearls (calcium-carbonate nacre)
fossil
Chert (variations include Flint or Jasper)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Jasper / Flint variant)
Microcrystalline Quartz (SiO2)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Fossiliferous limestone, possibly containing a brachiopod or bivalve fossil
Calcite-rich limestone (CaCO₃), with an apparent shell impression or shell fragment
fossil
Amber
Succinate (Fossilized Tree Resin)
mineraloid
Brown stone, likely a weathered chert or iron-stained rock
Unidentified brown lithic specimen; composition cannot be determined from the image
sedimentary
Petrified Wood
Silicified Wood
fossil
Bivalve Internal Mold Fossil
Steinkern (Bivalvia mold)
fossil
Amber
Succinite (approximate formula C10H16O)
mineraloid
Limestone with Lichen
Calcium Carbonate (CaCO3) with Endolithic/Epilithic Lichen
sedimentary
Weathered limestone pebble
Limestone, primarily calcite (CaCO₃)
sedimentary
Chert / Flint
Cryptocrystalline Quartz (SiO2)
sedimentary
Fossilized Coral
Anthozoa (Fossilized)
Sedimentary / Fossil
Honeycomb Coral Fossil
Favosites (extinct genus of tabulate coral)
sedimentary
Druzy Quartz Geode (Partially Open)
Silicon Dioxide (SiO2) within Sedimentary Host Rock
sedimentary
Honeycomb Calcite
Calcite (Calcium Carbonate, CaCO3)
sedimentary
Ironstone concretion (possibly a pyrite-bearing concretion)
Iron-oxide-cemented sedimentary concretion; exact mineral composition cannot be confirmed from the photograph
sedimentary
Coquina / Fossiliferous Limestone
Coquina (composed primarily of Calcium Carbonate / CaCO3)
sedimentary
Blue apatite (likely rough/tumbled specimen)
Apatite group, commonly fluorapatite — Ca5(PO4)3F
mineral
Silty Shale
Silty Shale (Fissile Sedimentary Rock)
sedimentary
Amber
Succinite (C10H16O)
mineraloid
Sandstone
Arenite (primarily composed of SiO2)
sedimentary
Graywacke
Lithic Sandstone (Graywacke)
sedimentary
Tufa (Calcareous Tufa)
Calcareous Tufa (Precipitated CaCO3)
sedimentary
Polished orbicular jasper
Orbicular jasper, an opaque microcrystalline quartz (SiO₂) aggregate with iron-oxide and other mineral inclusions
sedimentary
Chert (Iron-stained)
Microcrystalline silica (SiO2) with trace Iron oxide (Fe2O3)
sedimentary
Turritella Gastropod Fossil
Turritella (mollusk fossil in sedimentary matrix)
fossil