Ferruginous Sandstone (Grit)
Clastic Sedimentary (Ironstone-rich Sandstone)
Category
Browse sedimentary (chemically precipitated mineral) specimens identified by the Rock Identifier community.
Ferruginous Sandstone (Grit)
Clastic Sedimentary (Ironstone-rich Sandstone)
Limonite Concretion (Ironstone)
Limonite (FeO(OH)·nH2O) / Goethite
Carnelian
Carnelian (Cryptocrystalline Quartz, SiO2)
Quartz (Milky/Common)
Silicon Dioxide (SiO2)
Banded Agate (Dyed Purple)
Agate (Variety of Chalcedony/Quartz), SiO2
Chert (specifically Pink/Tan Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Graphite
Graphite (C)
Chert (often called Flint or Jasper when pigmented)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Bauxite
Bauxite (Al(OH)3 mixed with Fe2O3 and clay minerals)
Yellow Howlite (Dyed Magnesite/Howlite)
Dyed Ca2B5SiO9(OH)5 (Howlite) or MgCO3 (Magnesite)
Milky Quartz
Silicon Dioxide (SiO2)
Orange Calcite (Mexican Onyx)
Calcium Carbonate (CaCO3)
Optical Calcite (Iceland Spar)
Calcite (Calcium Carbonate, CaCO3)
Orange Calcite
Calcite (Calcium Carbonate, CaCO3)
Optical Calcite (Iceland Spar)
Calcite (Calcium Carbonate, CaCO3)
Quartz Geode (with Agate banding)
Silicon Dioxide (SiO2)
Vanadinite on Matrix
Vanadinite (Pb5(VO4)3Cl)
Chert (Chalky variety)
Microcrystalline Quartz (SiO2)
Chert (Yellow or Tan Chert)
Silicon Dioxide (SiO2)
Limonite (Hydrated Iron Oxide / Bog Iron)
FeO(OH)·nH2O
Yellow Calcite
Calcium Carbonate (CaCO3)
Native Gold (in Jewelry)
Gold (Au)
Sandstone with Liesegang Rings
Arenite with Iron Oxide Liesegang Banding
Dendrite (Manganese Oxide Dendrites)
Psilomelane or Pyrolusite on Matrix (typically MnO2)
Limestone
Calcium Carbonate (CaCO3)
Bauxite
Bauxite (Al(OH)3, AlO(OH))
Quartzite (Yellow/Orange variety)
Quartzite (primarily SiO2)
Orange Calcite
Calcium Carbonate (CaCO3)
Optical Calcite (Iceland Spar)
Calcite (Calcium Carbonate, CaCO3)
Honey Calcite
Calcium Carbonate (CaCO3)
Optical Calcite (Iceland Spar)
Calcium Carbonate (CaCO3)
Ironstone with Limonite/Goethite coating
Ferruginous Sedimentary Rock (contains Limonite FeO(OH)·nH2O)
White Marble
Metamorphosed Limestone (principally CaCO3)
Limonitic Sandstone (Stained Sandstone)
Clastic Sedimentary Rock with Iron Oxide (Limonite/Goethite) staining
Amethyst Geode
Silicon Dioxide with trace inclusions of Iron (SiO2)
Carnelian
Carnelian (variety of Chalcedony, SiO2)
Bauxite (Concretionary)
Bauxite (Al(OH)3, AlO(OH))
Chert (Iron-stained)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Nodule)
SiO2 (Microcrystalline Quartz)
Chert (variations include Flint/Jasper)
Cryptocrystalline Quartz (SiO2)
Kidney Stone (Renal Calculus)
Calcium oxalate monohydrate (Whewellite) / CaC2O4·H2O
Magnetite (Iron Ore)
Magnetite (Fe3O4)