Manganese Oxide Crust on Limestone
Manganese Oxides (e.g., Pyrolusite MnO2 or Romanechite) on CaCO3
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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Weathered Sandstone with Algae Growth
Arenite
sedimentary
Chert (likely chalcedony-rich flint)
Microcrystalline quartz, SiO₂ (quartz/chalcedony)
sedimentary
Weathered limestone
Calcite-rich carbonate rock (mostly CaCO₃), possibly fossiliferous limestone
sedimentary
Quartz Vein in Sandstone
Hydrothermal Quartz (SiO2) in Arenite
sedimentary
Tumbled garnet-bearing metamorphic rock
Likely garnet schist or garnet-bearing gneiss; garnet is commonly almandine, Fe₃Al₂(SiO₄)₃
metamorphic
Limestone Gravel
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Coal (Bituminous or Anthracite)
Organogenic Sedimentary Rock (Carbon)
sedimentary
Fossiliferous Limestone / Petrifaction
Sedimentary rock with fossil inclusions / Calcium Carbonate (CaCO3)
fossil
Weathered chert or silicified limestone nodule
Microcrystalline quartz (SiO₂), possibly with calcite (CaCO₃)
sedimentary
Fossiliferous Limestone Pebble
Calcium Carbonate (CaCO3) with Biogenic Inclusions
sedimentary
Chert (and associated Flint)
Silicon Dioxide (SiO2)
sedimentary
Chert (or Fossiliferous Limestone)
Microcrystalline Quartz (SiO2) / Calcium Carbonate (CaCO3)
sedimentary
Mookaite Jasper
Silicified Radiolarite (SiO2)
sedimentary
Chert (Nodule)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Quartz Geode
Crystalline Silicon Dioxide (SiO2) in Geode form
sedimentary
Chert (Arrowhead/Projectile Point)
Microcrystalline quartz (SiO2)
sedimentary
Banded Chert
Silicon Dioxide (SiO2)
sedimentary
Petrified wood
Silicified fossil wood, commonly quartz/chalcedony (SiO₂)
fossil
Chert
Silicon dioxide (SiO2)
Sedimentary
Chert (and Quartzite)
Microcrystalline silica (SiO2)
sedimentary
Limestone with Calcite Veining
Calcium Carbonate (CaCO3) - Biogenic/Chemical Sedimentary Rock
sedimentary
Rounded river pebble, likely quartz-rich sandstone or weathered quartzite
Tentative: quartz arenite (sandstone) or quartzite; chiefly SiO₂
sedimentary
Weathered fossil shell fragment
Indeterminate bioclastic carbonate, likely molluscan shell (calcium carbonate, commonly aragonite or calcite)
fossil
Vesicular Limestone with Borings
Fossiliferous Calcarenite (Calcium Carbonate, CaCO3)
sedimentary
Ironstone Nodule / Limonite Concretion
Iron-rich sedimentary concretion (FeO(OH)·nH2O / Fe2O3)
sedimentary
Fossiliferous Limestone
Fossiliferous Calcarenite (CaCO3)
sedimentary
Fossiliferous Limestone
Fossiliferous Calcite (CaCO3)
sedimentary
Coquina (Fossiliferous Limestone)
Biogenic Limestone (mostly CaCO3 / Calcium Carbonate)
sedimentary
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Quartz
Silicon Dioxide (SiO2)
mineral
Chert (Flint)
Chert (SiO2)
sedimentary
Fossiliferous Limestone
Fossiliferous Limestone (CaCO3)
sedimentary
Crushed Limestone
Calcium Carbonate (CaCO3)
sedimentary
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Amber
Succinite (Fossilized Tree Resin) - C10H16O
mineral
Quartz-rich sandstone (possibly quartzite)
Quartz arenite; if recrystallized, quartzite, composed predominantly of SiO₂
sedimentary
Chert Geode with Quartz Druzy
Microcrystalline Quartz (SiO2) with macrocrystalline Quartz
sedimentary
Chert
Microcrystalline quartz (SiO2)
sedimentary
Dendritic agate cabochon
Chalcedony (microcrystalline quartz, SiO₂) with manganese-oxide dendrites
gemstone
Fossiliferous Limestone (Coquina)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary