Sedimentary (Chemically Precipitated) Or Metamorphic

Orange Calcite

Calcite (Calcium Carbonate, CaCO3)

Orange Calcite

Calcite (Calcium Carbonate - CaCO3)

Yellow Calcite

Calcium Carbonate (CaCO3)

Green Calcite

Calcium Carbonate (CaCO3)

Orange Calcite

Calcium Carbonate (CaCO3)

Blue Calcite

Calcium Carbonate (CaCO3)

Botryoidal Pyrite

Iron Sulfide (FeS2)

Yellow Calcite

Calcium Carbonate (CaCO3)

Sandstone (with Liesegang rings or Oxidation)

Arenite (primarily Quartz SiO2 with Iron Oxide Fe2O3 staining)

Orange Calcite

Calcium Carbonate (CaCO3)

Limonite (Ironstone)

Limonite (FeO(OH)·nH2O)

Yellow Calcite

Calcite (Calcium Carbonate, CaCO3)

Agate

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Oolitic Limestone (Egg Stone)

Oolite (Chemical sedimentary rock, primarily CaCO3)

Chert Pebble with Quartz Veining

Microcrystalline Quartz (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

White Quartz

Silicon Dioxide (SiO2)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Limonite (Iron Ore/Sandstone mixture)

Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix

Septarian Nodule

Septarian Concretion (Composition: Calcite, Aragonite, and Limestone/Clay)

Sandstone (Ferruginous)

Arenite (Fe-rich SiO2)

Fossiliferous Limestone with Rugose Coral

Calcite (CaCO3) containing a Rugosa (Horn Coral) fossil

Ocean Jasper

Orbicular Jasper (Silicon Dioxide SiO2)

Banded Iron Formation (BIF)

Banded Iron Formation with Hematite and Jasper

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Hematite

Iron(III) oxide (Fe2O3)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Limonite (Yellow Ochre)

Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)

Septarian Nodule (Dragon Stone)

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

Ferruginous Breccia

Breccia with Iron-rich (Hematite/Goethite) Matrix

Milky or Iron-Stained Quartz

Quartz (Silicon Dioxide, SiO2)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Red Agate

Agate (Cryptocrystalline variety of Quartz, SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Clear Quartz (or Rock Crystal)

Quartz (SiO₂)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Aragonite (Onyx Marble)

Calcium Carbonate (CaCO3), Orthorhombic crystal system

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Barite Rose on Marcasite

Barium Sulfate (BaSO4) on Iron Sulfide (FeS2)

Hematite

Iron(III) oxide (Fe2O3)

Chalcedony (specifically Agate or Flint)

Silicon Dioxide (SiO₂)