Precious Opal
Hydrated amorphous silica (SiO2·nH2O)
Category
Browse sedimentary (anthropogenic) specimens identified by the Rock Identifier community.
Precious Opal
Hydrated amorphous silica (SiO2·nH2O)
Rhodochrosite
Manganese carbonate (MnCO3)
Hematite / Goethite (Iron Ore)
Iron Oxide (Fe2O3 / FeO(OH))
Quartz Geode (likely within Limestone or Dolomite matrix)
Quartz (SiO₂)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Pyrite on Limestone
Iron Disulfide (FeS2) in Calcium Carbonate (CaCO3) matrix
Quartzite River Rock
Quartzite (primarily SiO2)
Amber
Succinicum (Formula: C10H16O)
Yellow Quartzite or Yellow Jasper
Quartzite (primarily SiO2 with Iron oxide staining)
Quartz (Druzy)
Silicon Dioxide (SiO2)
Quartz Druze on Matrix
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Limonite (Hydrated Iron Oxide / Bog Iron)
FeO(OH)·nH2O
Quartz Crystal
Quartz (SiO₂)
Quartz
Silicon Dioxide (SiO2)
Pyrite
Pyrite (FeS2)
Chert (varietal: Jasper or Flint likely, but definitive identification is difficult from image)
SiO₂ (silicon dioxide)
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement of organic matter)
Chert (Tan/Yellow variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Sandstone
Arenite (primarily SiO2)
Chert (White Chert/Flint)
Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Siltstone
Siltstone (primarily SiO2 with Al2O3)
Chert (Commonly known as Flint or Jasper when pigmented)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (and Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Red Sandstone
Arenite (with Iron Oxide / Hematite), Formula: SiO2 (Quartz) + Fe2O3 (Hematite coating)
Red Sandstone
Clastic Terrigenous Sedimentary Rock (typically Hematitic Quartz Arenite or Arkose)
Crinoid Fossil in Limestone
Class Crinoidea in Carbonate Matrix (CaCO3)
Petrified Wood
Silicified Wood (SiO2)
Limonite (Ironstone Concretion)
Limonite (Hydrous ferric oxide mixture, FeO(OH)·nH2O)
Chert (Jasper)
Cryptocrystalline Quartz (SiO2)
Chert (Red Jasper)
Microcrystalline Quartz (SiO2)
Chert (and Limestone)
Silicon Dioxide (SiO2)
Chert (often called Flint for dark variants)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Red Sandstone
Arenite (Ferruginous Sandstone)
Siltstone
Siltstone
Chert (Pink/Red variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (White-Tan variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Calamites (Fossilized Horsetail)
Calamites suckowii (Family: Calamitaceae)
Crushed Limestone
Calcium Carbonate (CaCO3)
Sandstone
Arenite (primarily SiO2)
Geode with Quartz and Chalcedony
Silicon Dioxide (SiO2)