Chert (Agate/Flint variant)
Microcrystalline Quartz (SiO2)
Category
Browse sedimentary rock (specifically a clastic sedimentary rock formed into a cobble) specimens identified by the Rock Identifier community.
Chert (Agate/Flint variant)
Microcrystalline Quartz (SiO2)
Agate (or Chalcedony)
Silicon Dioxide (SiO2)
Carnelian Agate
Silicon Dioxide (SiO2) with iron oxide impurities
Sandstone
Arenite (variable SiO2 composition)
Jasper with Quartz Veining
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Coquina or Fossilized Shell Aggregate
Calcareous bioclastic sedimentary rock (CaCO3)
Ironstone (with possible Hematite/Limonite coating)
Ironstone (Fe-rich sedimentary rock)
Mica Schist
Mica Schist (primarily Muscovite and Quartz)
Chert (Brown variety / Common Jasper)
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Limestone
Calcium Carbonate (CaCO3)
Granite Cobble / Rounded Granite River Rock
Granite
Limonite (Iron Ore)
FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide mixture)
Bituminous Coal
Bituminous coal (Organic Sedimentary Rock)
Druzzy Quartz on Matrix
Silicon Dioxide (SiO2)
Pink Granite
Phaneritic Felsic Intrusive Igneous Rock
Basalt (Drill Core)
Mafic Volcanic Rock (Basalt)
Limonite (Iron Ore)
FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide)
Lignite (Brown Coal)
Humic Lignite (Carbonaceous sedimentary rock)
Limestone with Weathering Rind
Calcium Carbonate (CaCO3) - Bioclastic or Micritic Limestone
Basalt
Mafic volcanic rock (Basalt)
Dragon Stone
Ohko Stone (Argillaceous sedimentary rock)
Chert (Chalcedony/Agate)
Microcrystalline Quartz (SiO2)
Limestone
Calcium Carbonate (CaCO3)
Coquina Limestone (Fossiliferous Limestone)
Calcareous bioclastic sedimentary rock (CaCO3)
Granite Pegmatite
Phaneritic Plutonic Igneous Rock
Gneiss (with Mica and Quartz)
Gneissic Metamorphic Rock
Quartzite
Metamorphosed Quartz Sandstone (SiO2)
Mexican Crazy Lace Agate
Silicon Dioxide (SiO2) with iron and aluminum inclusions
Chert (Septarian or Nodular variety)
Microcrystalline Quartz (SiO2)
Pyrite in Quartz
Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)
Jasper (Iron-rich)
Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) impurities
Pink Granite
Granite (composed primarily of Quartz, K-Feldspar, and Plagioclase)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Clear Quartz
Quartz (Silicon Dioxide, SiO2)
Quartz Vein / Milky Quartz
Silicon Dioxide (SiO2)
Limestone Pebble
Calcium Carbonate (CaCO3)
Blue Chalcedony
Chalcedony (Silicon Dioxide, SiO2)
Agate
Silicon dioxide (SiO2)
Banded Calcite (often sold as 'Mexican Onyx')
Calcite (Calcium Carbonate, CaCO3)
Schist with Schorl (Black Tourmaline)
NaFe3Al6(BO3)3Si6O18(OH)4 (Schorl)
Agate
Silicon Dioxide (SiO2) - variety: Chalcedony