Sedimentary (Formed From Silica Deposits)

Browse sedimentary (formed from silica deposits) specimens identified by the Rock Identifier community.

Chalcedony (Agate/Chert)

Silicon Dioxide (SiO2)

mineral

Amber

Succinite (Organic Mineraloid) - C10H16O

mineral

Pyrite

Iron Disulfide (FeS2)

mineral

Green Fluorite (Beaded)

Fluorite (Calcium Fluoride, CaF2)

mineral

Sandstone

Arenite (composed primarily of SiO2)

sedimentary

Septarian Nodule (Thunder Egg)

Septarian Concretion (CaCO3 + CaMg(CO3)2 + SiO2)

sedimentary

Belemnite Fossil

Belemnitida (Order of extinct cephalopods)

sedimentary

Quartz (Smoky/Milky variety)

Silicon Dioxide (SiO2)

mineral

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

metamorphic

Quartz (River Pebble)

Silicon Dioxide (SiO2)

mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

mineral

Milky Quartz

Silicon Dioxide (SiO2)

mineral

Quartz with Iron Staining

Silicon Dioxide (SiO2) with Hematite inclusions

mineral

Amethyst (Faceted)

Silicon Dioxide with Iron impurities (SiO2)

mineral

Pyrite (Iron Pyrite) with Goethite Oxidation

Iron Sulfide (FeS2)

mineral

Sandstone (likely Graywacke or Arkosic varieties)

Arenite (composed primarily of SiO2)

sedimentary

Quartz Geode

Silicon Dioxide (SiO2) in a Secondary Formation

sedimentary

Banded Agate

Cryptocrystalline Quartz (SiO2)

mineral

Greenstone / Chert

Cryptocrystalline Quartz (SiO2) or Altered Basalt

sedimentary or metamorphic

Chalcedony (Banded/Mottled Variety)

Chalcedony (a cryptocrystalline variety of Quartz, SiO2)

Mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

mineral

Milky Quartz (Vein Quartz)

Silicon Dioxide (SiO2)

mineral

Pyrite

Iron Sulfide (FeS2)

mineral

Copper Nugget

Native Copper (Cu)

mineral

Limestone

Calcium Carbonate (CaCO3)

sedimentary

Orange Calcite Sphere

Calcium Carbonate (CaCO3)

mineral

Quartzite Pebble

Quartzite (mostly SiO2)

metamorphic

Limonite and Goethite (Ironstone)

Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)

sedimentary

Puddingstone (Conglomerate)

Conglomerate (clastic sedimentary rock)

sedimentary

Sandstone (Quartz-rich)

Arenite (composed mainly of SiO2)

sedimentary

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

mineral

Banded Calcite (Mexican Onyx)

Calcium Carbonate (CaCO3)

mineral

Chrysocolla in Quartz (Gem Silica)

Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O (Chrysocolla) / SiO2 (Quartz)

mineral

Amethyst (Chevron/Dream Amethyst)

Silicon Dioxide (SiO2) with iron impurities

mineral

Iron Ore / Ironstone Concretion

Mixture of iron oxide/hydroxide minerals, likely some combination of Hematite (Fe2O3), Goethite (α-FeOOH), and Limonite (a general term for hydrated iron oxides of variable composition) or potentially Bauxite (a mixture of aluminum hydroxides, often with iron oxides, (Al(OH)3) and FeO(OH)). The visual characteristics strongly suggest iron-rich material.

Mineral, specifically an iron ore