Shale
Fissile mudrock (composed primarily of clay minerals and quartz)
sedimentary
Category
Sedimentary (Silicified Fossiliferous Chalcedony)
Browse sedimentary (silicified fossiliferous chalcedony) specimens identified by the Rock Identifier community.
Pyrite
Iron Disulfide (FeS2)
mineral
Sedimentary Breccia
Breccia (Clastic Sedimentary Rock)
sedimentary
Sedimentary Breccia
Clastic Breccia (CaCO3/SiO2 matrix)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Shale
Fissile mudrock (composed of clay-sized particles and detrital grains)
sedimentary
Shale
Fissile Mudstone (primarily composed of phyllosilicate minerals like kaolinite, montmorillonite, and illite)
sedimentary
Shale
Clastic sedimentary rock (primarily clay and silt minerals)
sedimentary
Celestine (Celestite)
Strontium sulfate (SrSO4)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Halite (Rock Salt)
Halite (Sodium Chloride, NaCl)
mineral
Shale with Siltstone layering
Sedimentary Clastic Rock (Mudstone/Shale)
sedimentary
Sandstone (Quartz Sandstone)
Arenite (primarily SiO2)
sedimentary
Carnelian
Carnelian (SiO2 with Iron oxide impurities)
Mineral (Chalcedony variety)
Bloodstone / Heliotrope
Silicon dioxide (SiO2) with inclusions
Mineral (variety of Chalcedony)
Tree Agate
Silicon Dioxide with Chlorite inclusions (SiO2)
Mineral (Variety of Chalcedony)
Moqui Marble (Concretion)
Iron Oxide Concretion (Hematite-cemented Sandstone)
sedimentary
Limonite with Trace Fossils
Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)
sedimentary
Chert (Jasper/Opaline variety)
Silicon Dioxide (SiO2)
sedimentary
Yellow Calcite
Calcium Carbonate (CaCO3)
mineral
Devil's Toenail
Gryphaea (extinct genus of foam oysters, typically composed of Calcite CaCO3)
sedimentary
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Banded Agate (specifically Eye Agate / Chalcedony)
Agate (Cryptocrystalline variety of Quartz, SiO2)
mineral
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
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxides
Mineral (Variety of Chalcedony)
Moss Agate
Silicon Dioxide (SiO2) with mineral inclusions of hornblende or chlorite
Mineral (variety of Chalcedony)
Amazonite
KAlSi3O8 (Potassium Feldspar, variety of Microcline)
Mineral
Chert (Tan/Yellow variety)
Microcrystalline quartz (SiO2)
sedimentary
Sandstone (Ferruginous)
Arenite with Iron Oxide (Fe2O3) cement
sedimentary
Lepidodendron Fossil in Sandstone
Lepidodendron (Lycophytina, Lepidodendrales)
sedimentary
Sandstone (with ripple marks)
Arenite / Quartz Sandstone
sedimentary
Chert (specifically Gray/Blue-Gray Chert)
Chert (SiO2)
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Blue Apatite
Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)
mineral
Sandstone (Micaceous)
Arenite (composed primarily of SiO2)
sedimentary
Sandstone (Water-worn Pebble)
Clastic Sedimentary Rock (primarily SiO2)
sedimentary
Tiger's Eye
Tiger's Eye (a variety of Chalcedony, which is a microcrystalline quartz with fibrous inclusions of oxidized crocidolite)
Mineral
Knightia Fossil in Limestone
Knightia eocaena in micritic limestone
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) in Host Rock
sedimentary
Orange Calcite
Calcium Carbonate (CaCO3)
mineral