Sandstone
Sedimentary Rock (Quartz Sandstone)
Category
Browse sedimentary (man made) specimens identified by the Rock Identifier community.
Sandstone
Sedimentary Rock (Quartz Sandstone)
Bauxite
Bauxite (Al(OH)3, AlO(OH))
Coquina
Bioclastic Limestone (Calcium Carbonate, CaCO3)
Coquina
Biogenic Limestone (mostly Calcium Carbonate, CaCO3)
Chert (often called Flint or Jasper)
Microcrystalline Quartz (SiO2)
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Jasper (Iron-rich Chalcedony)
Jasper (Microcrystalline Silicon Dioxide, SiO2 plus iron oxide impurities)
Unidentified polished dark gemstone cabochon
Possibly hematite, obsidian, jet, or dark agate; image insufficient for a definitive identification
Natural freshwater pearls
Pearl (nacreous calcium carbonate; chiefly aragonite, CaCO₃)
Crushed Stone / Gravel
Aggregatus saxum (variable mineral composition)
Sandstone
Sedimentary Rock (Quartz Sandstone)
Fossilized Shark Tooth (Sand Tiger)
Carcharias sp. (Fossilized Tooth)
Chert (Yellow Jasper/Flint)
Chert (Microcrystalline Silicon Dioxide, SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Coquina
Coquina (Biogenic Limestone / CaCO3)
Coquina Limestone
Coquina (Biogenic Limestone)
Flint (or Chert with cortex)
Silicon dioxide (SiO2)
Chert (with Desert Varnish/Iron Stain)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Flint)
Silicon Dioxide (SiO2)
Coquina / Fossiliferous Limestone
Coquina (composed primarily of Calcium Carbonate / CaCO3)
Chert or silicified sedimentary fragment (tentative)
Microcrystalline quartz (SiO₂), possibly silicified limestone or fossil-bearing chert
Coquina
Biogenic Limestone (Calcite, CaCO3)
Coquina
Biogenic Limestone (Coquina)
Chert (Jasper)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert (Jasper type)
Microcrystalline Quartz (SiO2)
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Coral Rock (Coquina)
Biogenic Limestone (Calcium Carbonate - CaCO3)
Dark gneiss or migmatitic amphibolite
Band ed gneiss; composition likely quartz–feldspar–biotite/amphibole, possibly migmatite
Flint
Silicon Dioxide (SiO2) - Microcrystalline Quartz / Chert
Pyrite
Iron Disulfide (FeS2)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Petrified Wood (Silicified Wood)
Silicified Paleoflora (mainly Quartz, SiO2)
Pyrite
Iron Disulfide (FeS2)
Chert (Flint)
Chert (Cryptocrystalline Silica, SiO2)
Quartz (likely Chalcedony or Chert)
Silicon Dioxide (SiO2)
Chert (varietal Flint)
Microcrystalline quartz (SiO2)
Pearl
Calcium Carbonate (CaCO3) with Conchiolin
Inscribed limestone fragment
Calcitic limestone (primarily CaCO₃), possibly marble if recrystallized
Crinoid Fossil in Limestone
Crinoid columnal (Class Crinoidea) in biomicrite
Fossil shark tooth in sediment
Likely fossilized shark tooth, possibly *Carcharhinus* or *Otodus*; exact identification requires the tooth’s full morphology and locality
Chert
Sedimentary cryptocrystalline quartz (SiO2)