Banded Chert
Silicon Dioxide (SiO2)
Category
Browse sedimentary (chemically precipitated mineral) specimens identified by the Rock Identifier community.
Banded Chert
Silicon Dioxide (SiO2)
Fossiliferous Limestone
Calcium Carbonate (CaCO3) with Biogenic Inclusions
Chert (Flint)
Chert (SiO2)
Chert (Flint) Nodule
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert Nodule / Ironstone Concretion
Microcrystalline Quartz (SiO2) with Iron Oxides
Banded Iron Formation (Fragment)
Banded Iron Formation (BIF)
Honey-colored calcite
Calcite (calcium carbonate, CaCO₃), likely rough or partly polished
Banded Jasper with Hematite or Quartz
Silicon Dioxide (SiO2) with impurities
Chalcedony (Agate / Quartz Geode Fragment)
Silicon Dioxide (SiO2)
Chert or chalcedony nodule
Microcrystalline quartz (SiO₂), possibly weathered chert
Orange Calcite
Calcium Carbonate (CaCO3)
Orange Calcite
Calcium Carbonate (CaCO3)
Aragonite (Onyx Marble)
Calcium Carbonate (CaCO3), Orthorhombic crystal system
Blue Calcite
Calcium Carbonate (CaCO3)
Blue calcite
Calcite (CaCO₃), likely blue calcite with white carbonate matrix
Blue Calcite
Calcium Carbonate (CaCO3)
Hematite
Iron(III) oxide (Fe2O3)
Jasper
Silicon dioxide (Microcrystalline quartz, SiO2 with iron oxide impurities)
Agate
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Septarian Nodule
Septarian Concretion (Composition: Calcite, Aragonite, and Limestone/Clay)
Amethyst Geode
Amethyst/Purple Quartz (SiO2)
Pyrite-bearing Rock / Pyrite Ore
Iron Sulfide (FeS2) in host rock matrix
Orange Calcite (Polished Sphere)
Calcium Carbonate (CaCO3)
Limonite (Iron Ore/Bog Iron)
Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)
Quartz-veined Sandstone
Sedimentary rock with quartz vein (SiO2)
Red Sandstone
Quartzose Sandstone (primarily quartz grains cemented by iron oxides)
Chert (Hagstone / Lucky Stone)
Microcrystalline Quartz (SiO2)
Blue Calcite
Calcium Carbonate (CaCO3)
Honey Calcite
Calcium Carbonate (CaCO3)
Ferruginous Sandstone (Gozzanous)
SiO2 (Quartz) with FeO(OH) (Goethite) or Fe2O3 (Hematite) coating
Yellow Ochre / Limonite
Limonite (FeO(OH)·nH2O)
Orange calcite (honey calcite)
Calcite, calcium carbonate (CaCO₃)
Yellow calcite fragment
Calcite (CaCO₃), likely honey/yellow calcite
Blue apatite (likely dyed or enhanced)
Apatite group; fluorapatite, Ca5(PO4)3F, is the common blue variety
Chert / Chalcedony Nodules
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Green Calcite
Calcium Carbonate (CaCO3)
Yellow Calcite
Calcium Carbonate (CaCO3)
Rough Green Calcite
Calcite (Calcium Carbonate, CaCO3)
Orange Calcite
Calcite (Calcium Carbonate, CaCO3)
Sandstone with Iron Staining
Clastic sedimentary rock (SiO2 with iron oxides)
Banded iron formation (ironstone)
BIF; hematite–magnetite–quartz/chert assemblage
Chalcedony (specifically Agate or Flint)
Silicon Dioxide (SiO₂)