Sedimentary (Secondary Formation)

Weathered river cobble, possibly sandstone or volcanic tuff

Indeterminate lithology; likely fine-grained sandstone/siltstone, with possible iron-oxide veining

Rhodochrosite

Manganese carbonate (MnCO3)

Hematite / Goethite (Iron Ore)

Iron Oxide (Fe2O3 / FeO(OH))

Quartz Geode / Druzy Quartz Node

Silicon Dioxide (SiO2)

Botryoidal Hematite (Kidney Ore)

Hematite (Fe2O3)

Orange Calcite

Calcium Carbonate (CaCO3)

Blue Calcite

Calcium Carbonate (CaCO3)

Gold Flake

Native Gold (Au)

Agate (specifically Chalcedony/Banded Agate)

Silicon Dioxide (SiO2)

Hematite (Nodular or Botryoidal)

Iron(III) oxide (Fe2O3)

Hematite

Iron(III) oxide (Fe2O3)

Jasper Agate

Chalcedony (Silicon Dioxide - SiO2)

Agate Nodule (partially vuggy Quartz)

Silicon Dioxide (SiO2)

Banded Chert or Agate

Silicon Dioxide (SiO2)

Green Calcite

Calcium Carbonate (CaCO3)

Sandstone

Arenite (primary component SiO2)

Quartz Geode

Quartz (Silicon Dioxide, SiO2) Geode

Banded Iron Formation (BIF) / Banded Sandstone Nodule

Hematite-rich Sandstone / Ferruginous Chert

River Pebble (likely Quartzite or Chert)

Sedimentary Clast (Silicon Dioxide dominant)

Limonite (Iron Ore)

Limonite (Hydrous iron(III) oxide-hydroxide mixture, FeO(OH)·nH2O)

Rhodochrosite

Manganese Carbonate (MnCO3)

Turquoise and Hematite

CuAl6(PO4)4(OH)8·4H2O (Turquoise) and Fe2O3 (Hematite)

Chert (Jasper/Pink Chert)

Silicon Dioxide (SiO2)

Hematite

Iron(III) oxide (Fe2O3)

Agate (specifically, a slice of a Blue Lace or Chalcedony Agate nodule)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Banded Chert / Agate

Silicon Dioxide (SiO2)

Rhodonite

Manganese Silicate (Mn,Fe,Mg,Ca)SiO3

Native Sulfur

Sulfur (S8)

Satin Spar (Selenite)

Gypsum (CaSO4·2H2O)

Specular Hematite

Hematite (Fe2O3)

Weathered Sedimentary Rock with Liesegang Rings

Sandstone or Siltstone with Iron Oxide Banding

Red Jasper

SiO2 (Silicon Dioxide) with Fe2O3 (Hematite)

Ironstone Matrix with Jasper / Chert

Ferruginous Chert / Limonitic Jasper (SiO2 with Fe-oxides)

Sandstone Concretion with Quartz Center

Sedimentary Clastic Rock (SiO2 matrix with Quartz core)

Chert (Jasper variation)

Microcrystalline Quartz (SiO2)

Green Jasper

Microcrystalline Quartz (Chalcedony), SiO2

Agate (Water-Worn Pebble)

Silicon Dioxide (SiO2) - Chalcedony

Chert (with Quartz Veining)

Microcrystalline silicon dioxide (SiO2)

Variscite (or potentially a turquoise/variscite matrix cabochon, or an impression jasper)

AlPO4·2H2O (Variscite) or related phosphate/silicate material depending on exact composition

Botryoidal Chalcedony (Agate)

Cryptocrystalline Quartz (SiO2)

Jasper or Chert with Quartz Vugs

Silicon Dioxide (SiO2)

Chalcedony (Agate)

Silicon Dioxide (SiO2)