Sedimentary (Physico Chemical Precipitate)

Banded iron formation fragment (likely hematite–magnetite ironstone)

Banded iron formation; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and microcrystalline quartz (SiO₂)

Ironstone Concretion (Limonite/Goethite)

Goethite-rich Concretion (FeO(OH))

Quartz (Milky/Bull Quartz)

Silicon Dioxide (SiO2)

Limestone with Calcite Veining

Calcium Carbonate (CaCO3)

Weathered quartz-rich rock, possibly chert or quartzite

Indeterminate; likely microcrystalline quartz (SiO₂), possibly quartzite or chert

Quartz

Silicon Dioxide (SiO2)

Honey Calcite

Calcium Carbonate (CaCO3)

Banded iron formation fragment (tumbled iron-rich rock)

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

Banded iron formation pebble

Banded iron formation (BIF), chiefly hematite/magnetite with chert or jasper

Agate

Chalcedony (Silicon Dioxide, SiO2)

Quartz-veined Limestone

Sedimentary limestone with quartz/calcite veinlets

Yellow jasper / iron-rich chert

Microcrystalline quartz (SiO₂), commonly colored by iron oxides

Chert (Light Grey / Flint variant)

Cryptocrystalline Quartz (SiO2)

Hematite Nodular Iron Ore

Hematite (Fe2O3)

Weathered limestone

Micritic limestone, primarily calcite (CaCO₃)

Likely limestone fragment

Calcite-rich carbonate rock; primarily calcium carbonate (CaCO₃)

Chert (Iron-Stained)

Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3) impurities

Banded iron formation fragment (likely hematite–magnetite ironstone)

BIF; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and silica as microcrystalline quartz (SiO₂)

Brown chert or flint pebble

Microcrystalline quartz (SiO₂), likely chert

Orange Calcite

Calcium Carbonate (CaCO3)

Amethyst Geode Fragment

Quartz (SiO2) with trace iron impurities

Clear Quartz (Rock Crystal) Bracelet

Silicon Dioxide (SiO2)

Likely calcite fragment

Calcite (calcium carbonate, CaCO₃)

Calcite crystal fragment

Calcite (calcium carbonate, CaCO₃)

Weathered iron-rich concretion or sedimentary rock

Likely ferruginous sandstone or ironstone concretion; exact identification is not possible from the image alone

Honey calcite crystal

Calcite (calcium carbonate, CaCO₃)

Blue Calcite

Calcium Carbonate (CaCO3)

Jasper with Quartz Vein

Microcrystalline quartz (SiO2) with impurities

Yellow Quartz

Silicon Dioxide (SiO2)

Quartz and Mixed Sedimentary Rocks

Silicon Dioxide (SiO2) mixed with various clastic sedimentary lithologies

Weathered limestone or dolostone

Calcite-rich limestone (CaCO₃), possibly dolomite-bearing

Jasper

Microcrystalline Quartz (SiO2)

Banded jasper / iron-rich chert (probable)

Microcrystalline quartz (SiO₂) with iron oxides/hydroxides and clay minerals

Banded iron formation (iron-rich jasper/chert)

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

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)

Tumbled yellow chalcedony (likely yellow jasper)

Microcrystalline quartz, SiO₂; chalcedony/jasper variety

Chert with Manganese Dendrites / River Silt Overlays

Cryptocrystalline Quartz (SiO2) with Manganese Oxides

Sandstone (with Liesegang rings or Oxidation)

Arenite (primarily Quartz SiO2 with Iron Oxide Fe2O3 staining)

Chert or flint nodule

Microcrystalline quartz (SiO₂), likely chalcedony-rich chert

Banded iron formation (ironstone)

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