Sedimentary (Chemically Precipitated) Or Metamorphic

Quartz

Silicon dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Pyrite

Iron Sulfide (FeS2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz (Druzy)

Silicon Dioxide (SiO2)

River Chalcedony / Agate

Chalcedony (Silicon Dioxide, SiO2)

Carnelian Agate

Carnelian (Silicon Dioxide - SiO2)

Weathered quartz-rich rock, possibly quartzite or vein quartz

Quartz-dominant aggregate; chiefly silicon dioxide (SiO₂), possibly quartzite with iron-oxide staining

Banded iron formation (iron-rich jasper/chert)

Banded iron formation, chiefly quartz (SiO₂) with hematite, magnetite, and/or goethite (Fe oxides/hydroxides)

Chert / Flint Pebble with Fossil Cavity

Silicon Dioxide (SiO2)

Banded iron formation fragment (likely jasper-rich ironstone)

Banded iron formation (BIF), commonly hematite/goethite with chert or jasper; Fe₂O₃/FeO(OH) and SiO₂

River Pebble (Greywacke or Chert mix)

Silicon Dioxide (SiO2) with varying mineral impurities

Chert Pebble with Quartz Veining

Microcrystalline Quartz (SiO2)

Iron-rich metamorphic rock, likely banded iron formation fragment

Banded iron formation (BIF), chiefly hematite–magnetite with chert; exact identification requires testing

Quartz Vein in Metamorphic Rock

Quartz-veined Schist or Gneiss

Orange Calcite

Calcium Carbonate (CaCO3)

Banded Iron Formation (BIF)

Banded Iron Formation (Magnetite-Hematite-Chert)

Pyrite

Iron Sulfide (FeS2)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Chert with Manganese Dendrites / River Silt Overlays

Cryptocrystalline Quartz (SiO2) with Manganese Oxides

Quartz (Grain/Fragment)

Silicon Dioxide (SiO2)

Likely ironstone pebble

Iron-oxide-rich concretion, composed mainly of goethite and/or hematite

Tumbled yellow chalcedony (likely yellow jasper)

Microcrystalline quartz, SiO₂; chalcedony/jasper variety

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Quartz pebble

Silicon dioxide (SiO2)

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Sandstone (with Liesegang rings or Oxidation)

Arenite (primarily Quartz SiO2 with Iron Oxide Fe2O3 staining)

White quartz (likely milky quartz)

Quartz, silicon dioxide (SiO₂)

Quartzite

Metamorphic Quartzite (SiO2)

Quartzite

Metamorphic Quartzite (SiO2)

White Quartz Pebble

Crystalline Silicon Dioxide (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Chert or flint nodule

Microcrystalline quartz (SiO₂), likely chalcedony-rich chert

Quartz Pebble

Silicon Dioxide (SiO2)

Banded iron formation (ironstone)

Banded iron formation, chiefly hematite/magnetite with chert (SiO₂)

Banded Iron Formation (BIF)

Banded Iron Formation with Hematite and Jasper

Banded iron formation (ironstone), likely hematite–magnetite jasper

Banded iron formation (BIF), chiefly Fe₂O₃ hematite, Fe₃O₄ magnetite, and SiO₂ quartz/chert

Liesegang Banded Sandstone (Concretion / Weathered Pebble)

Sandstone showing Liesegang rings / Weathering rind (SiO2 with iron oxides)

Ironstone (iron-rich sandstone or concretion)

Ferruginous sandstone, cemented by iron oxides/hydroxides such as hematite (Fe₂O₃) and goethite (FeO(OH))