Ferruginous Quartz on Ironstone
Silicon Dioxide (SiO2) with Hematite (Fe2O3)
metamorphic
Category
Sedimentary (Secondary Formation)
Browse sedimentary (secondary formation) specimens identified by the Rock Identifier community.
Carnelian Agate
Silicon Dioxide (SiO2) with iron oxide impurities
mineral
Conglomerate (Red Sandstone variety)
Clastic Sedimentary Rock (Conglomeratic Sandstone)
sedimentary
Zebra Rock (Zebra Stone / Ribbon Stone)
Siltstone with Ferruginous Banding (Primarily Quartz, Kaolinite, and Hematite)
sedimentary
Red Sandstone
Arenite (high iron oxide content)
sedimentary
Tree Agate
Silicon Dioxide (SiO2) with Chlorite/Manganese inclusions
sedimentary
Dinosaur Bone (Gembone)
Petrified Dinosaur Bone (Apatite/Silica replacement)
sedimentary
Red Sandstone
Arenite (Fe2O3-rich)
sedimentary
Red Sandstone
Arenite
sedimentary
Pyrite on Limestone
Iron Disulfide (FeS2) in Calcium Carbonate (CaCO3) matrix
sedimentary (matrix) / mineral (inclusion)
Druzy Quartz Geode (likely Smokey Quartz variety)
Silicon Dioxide (SiO2) - specifically a geode formation lined with druzy quartz crystals, with a likely brownish hue indicating smokey quartz.
Mineral structure/Rock
Iridescent Ammonite Fossil
Ammonoidea (subclass); Composition: Aragonite (Calcium Carbonate, CaCO3) often replaced by Calcite or Pyrite
sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with iron hydroxides (Goethite)
sedimentary
Tufa
Calcareous Tufa (CaCO3)
sedimentary
Chert (Jasper)
Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Pink/Red variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Rhodolite Garnet
Magnesium Aluminum Silicate; formula: (Mg,Fe)3Al2(SiO4)3
mineral
Gneiss (specifically Granitic Gneiss)
Gneiss (composed primarily of Quartz, Feldspar, and Biotite/Amphibole)
metamorphic
Hematite
Hematite (Fe2O3)
Mineral
Limestone (Porous/Travertine variant)
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Chert (Banded Variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with hydrated iron oxide impurities
sedimentary
Quartz (Crystal/Druzy Quartz)
Quartz (SiO₂)
Mineral
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Sandstone
Arenite (primarily Quartz, SiO2)
sedimentary
Sandstone
Arenite (variable SiO2 composition)
sedimentary
Moqui Marble
Iron Oxide Concretion (Limonite/Hematite over Sandstone)
sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Iron Ore (Hematite/Magnetite mixture)
Ferrous Oxide (Fe2O3 / Fe3O4)
sedimentary
Knightia Fossil in Limestone
Knightia eocaena in micritic limestone
sedimentary
Fancy Jasper
Chalcedony (cryptocrystalline quartz) with inclusions
Mineral
Sandstone (Quartzose)
Arenite (primarily SiO2)
sedimentary
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Sandstone (Quartz Arenite)
Sandstone (Chemical formula: primarily SiO2)
sedimentary
Sandstone (specifically Flagstone)
Arenite (primarily composed of SiO2)
sedimentary
Sandstone (Ferruginous)
Arenite (primarily SiO2 with iron oxide cement)
sedimentary
Agate Geode
Silicon Dioxide (SiO2) - Banded Chalcedony
mineral
Sandstone
Arenite (primarily SiO2)
sedimentary
Chert Pebble with Quartz Veining
Microcrystalline Quartz (SiO2)
sedimentary
Limestone (Brecciated/Recrystallized)
Calcium Carbonate (CaCO3)
sedimentary