Coquina with Calcite Crystals
Calcareous Bioclastic Grainstone (CaCO3)
sedimentary
Category
Sedimentary (Biogenic Sediment Or Biological Remain)
Browse sedimentary (biogenic sediment or biological remain) specimens identified by the Rock Identifier community.
Learn about Sedimentary (Biogenic Sediment Or Biological Remain) in the encyclopedia
View all →
Limestone
Sedimentary rock composed primarily of Calcite (CaCO3)
sedimentary
Banded Chert or Mudstone
Chert (Silicon dioxide, SiO2) or Mudstone
sedimentary
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Tumbled blue-green stone, likely amazonite-bearing granite or microcline
Amazonite (green microcline, KAlSi₃O₈) in a granitic host; exact identification uncertain from photo
igneous
Fossilized Brachiopod
Brachiopoda (likely Order Spiriferida or Productida)
fossil
Fossil ammonite
Ammonoidea (likely a ribbed, involute ammonite; exact genus requires locality and preservation details)
fossil
Chert (and Fossilized Brachiopod shell)
Sedimentary Cryptocrystalline Quartz (SiO2)
sedimentary
Pearl necklace
Pearl—biogenic calcium carbonate, primarily aragonite (CaCO₃)
gemstone
Dendritic Agate or Manganese Nodule in Chert/Limestone
Silicon Dioxide (SiO2) with Manganese Oxide (MnO2) inclusions
sedimentary
Fossilized Shark Tooth (Otodus)
Otodus sp. (calcium phosphate/hydroxylellite)
sedimentary
Banded Chert (Flint)
Cryptocrystalline Quartz (SiO2)
sedimentary
Limestone with Fossil Fragment
Sedimentary carbonate rock (CaCO3)
sedimentary
Possible fossilized shell or coral fragment
Indeterminate biogenic carbonate, likely calcite (CaCO₃)
fossil
Fossilized oyster or other bivalve shell
Calcitic bioclast, commonly Ostrea spp. or Exogyra spp.
fossil
Red coral (polished coral beads)
Corallium spp.; chiefly calcium carbonate (CaCO₃, calcite)
gemstone
Pyrite
Iron Sulfide (FeS2)
mineral
Blue Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Chert (or Flint)
Chert (cryptocrystalline quartz), SiO2
Sedimentary
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
metamorphic
Tumbled tan stone, likely calcite or limestone
Calcite (CaCO₃), possibly microcrystalline limestone
mineral
Calcite
Calcium Carbonate (CaCO3)
mineral
Amber (Copal)
Fossilized Tree Resin (C10H16O)
mineral
Chert (Jasper variety)
Silicon Dioxide (SiO2)
sedimentary
Fossilized ammonite
Ammonoidea (likely a small, chambered ammonite fossil)
fossil
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Tufa
Calcareous Tufa (CaCO3)
sedimentary
Chert
Chert (SiO2)
sedimentary
Fossiliferous Limestone (Coquina / Shell Limestone)
Bioclastic Limestone (CaCO3)
sedimentary
Chert (likely Flint)
Cryptocrystalline Quartz (SiO2)
sedimentary
Calcite
Calcium Carbonate (CaCO3)
mineral
Weathered Quartzite or Chert Pebble
Silicon Dioxide (SiO2)
metamorphic or sedimentary
Pebble (likely Quartz or Chert)
SiO₂ (Silicon Dioxide) - referring to the likely main mineral composition, Quartz. If it's chert, the scientific name remains SiO₂ with a microcrystalline structure.
Sedimentary Rock
Chert (Jasper/Flint Pebble)
Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)
sedimentary
Moss-covered Rock Fragment
Weathered Rock Fragment with Epilithic Growth
sedimentary
Fossiliferous Limestone
Calcium Carbonate (CaCO3) with Bioclastic Inclusions
sedimentary
Amber
Succinite (specifically for Baltic Amber), Formula: C10H16O
Organic Gemstone (often associated with Sedimentary sequences)
Amber
Succinite (fossilized resin, C10H16O)
mineral
Banded Siltstone / Mudstone Pebble
Siltstone / Argillite
sedimentary
Limonitic Sandstone with Inclusion
Limonitic Quartz Sandstone (primarily SiO2 with FeO(OH)·nH2O)
sedimentary
Chert (Jasper/Mudstone variant)
Silicon Dioxide (SiO2)
sedimentary