Sedimentary (Chemically Precipitated)

Chert / Chalcedony Nodules

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Blue Calcite

Calcium Carbonate (CaCO3)

Honey Calcite

Calcium Carbonate (CaCO3)

Blue calcite (probable)

Calcite, calcium carbonate (CaCO₃)

Banded iron formation pebble (likely jasper-rich ironstone)

Banded iron formation (BIF), composed mainly of hematite/magnetite and microcrystalline quartz (chert/jasper)

Limestone

Calcium Carbonate (CaCO3)

Weathered metallic sulfide-bearing rock, possibly pyrite-rich ore

Tentatively pyrite (FeS₂) with iron oxides and host rock; exact identification requires testing

Quartz Geode / Druzy Quartz Node

Silicon Dioxide (SiO2)

Ironstone Nodule

Ironstone (Ferruginous Rock)

Orange Calcite

Calcium Carbonate (CaCO3)

Yellow Calcite

Calcium Carbonate (CaCO3)

Chert Nodule (with Geode cavity)

Cryptocrystalline Quartz (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz (Peach/Orange)

Silicon Dioxide (SiO2)

Pyrite

Iron Sulfide (FeS2)

Optical Calcite

CaCO3 (Calcium Carbonate)

Yellow Calcite

Calcium Carbonate (CaCO3)

Dendritic Limestone

CaCO3 with manganese oxide dendrites

Yellow calcite fragment

Calcite (CaCO₃), likely honey/yellow calcite

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Jasper (Iron-stained Chert)

Silicon Dioxide (SiO2) with iron oxide inclusions

Hematite

Iron(III) oxide (Fe2O3)

Chalcedony (specifically Agate or Flint)

Silicon Dioxide (SiO₂)

Orange Calcite

Calcium Carbonate (CaCO3)

Calcareous Tufa (Tufa)

Precipitated Calcium Carbonate (CaCO3)

Tufa (Calcareous Tufa)

Calcareous Tufa (Precipitated CaCO3)

Barite Rose on Marcasite

Barium Sulfate (BaSO4) on Iron Sulfide (FeS2)

Honey calcite crystal

Calcite (calcium carbonate, CaCO₃)

Water-worn chalcedony pebble

Chalcedony, microcrystalline SiO₂; possibly iron-stained agate

Banded iron formation (ironstone)

BIF; hematite–magnetite–quartz/chert assemblage

Pyrite-bearing rock (likely pyrite-rich schist or quartz-bearing sulfide ore)

Pyrite (FeS₂) in a rock matrix; exact host rock cannot be confirmed from the photo

Agate

Agate (Silicon Dioxide - SiO2)

Banded iron formation (ironstone), possibly hematite–magnetite-rich

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

Banded iron formation fragment (polished ironstone)

Banded iron formation; hematite/magnetite-rich chert, commonly approximated as Fe₂O₃–Fe₃O₄ with SiO₂

Banded iron formation fragment (likely hematite–magnetite-rich ironstone)

Banded iron formation; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and silica/chert (SiO₂)

Chert or chalcedony nodule

Microcrystalline quartz (SiO₂), possibly weathered chert

Jasper

Silicon Dioxide (SiO2), Microcrystalline Quartz

Quartz Geode with Chalcedony

Silicon Dioxide (SiO2)

Quartz Geode (Unbroken)

Silicon Dioxide (SiO2)

Green Jasper / Chert Pebbles

Microcrystalline Quartz (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Orange Calcite

Calcium Carbonate (CaCO3)