Sedimentary (Chemically Precipitated) Or Metamorphic

Polished banded chert or jasper

Microcrystalline quartz (SiO₂), likely iron- and manganese-stained chert/jasper

Tufa

Calcareous Tufa (Calcium Carbonate, CaCO3)

Yellow jasper / iron-rich chert

Microcrystalline quartz (SiO₂), commonly colored by iron oxides

Iron-rich chert or jasper

Microcrystalline quartz (SiO₂), colored by hematite/goethite inclusions

Calcite

Calcium Carbonate (CaCO3)

Rhyolitic jasper or iron-stained chert

Microcrystalline quartz (SiO₂), likely with hematite/goethite staining

Orange Calcite

Calcium Carbonate (CaCO3)

Green Calcite

Calcium Carbonate (CaCO3)

Orange Calcite

Calcium Carbonate (CaCO3)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Pyrite

Iron Sulfide (FeS2)

Pyrite

Iron Sulfide (FeS2)

Light-colored limestone

Calcite-rich limestone (CaCO₃)

Banded calcite (onyx marble)

Calcite, CaCO₃; commonly sold as Mexican or Pakistani onyx marble

Blue Calcite

Calcium Carbonate (CaCO3)

Quartz

Silicon Dioxide (SiO2)

Pale limestone

Limestone, predominantly calcite (CaCO₃)

Likely red jasper or iron-rich chert

Microcrystalline quartz (SiO₂) colored by hematite/goethite

Chalky limestone fragment

Micritic limestone, chiefly calcite (CaCO₃)

Weathered iron-rich chert or jasper

Microcrystalline quartz (SiO₂), variably stained by iron oxides

Weathered iron-rich chert or jasper

Microcrystalline quartz (SiO₂), variably stained by iron oxides/hydroxides

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Weathered iron-rich rock, possibly hematite-bearing basalt or ironstone

Uncertain; likely Fe-oxide-rich basalt/ironstone containing hematite (Fe₂O₃), magnetite (Fe₃O₄), and silicate minerals

Orange Calcite

Calcite (Calcium Carbonate, CaCO3)

Red sandstone or iron-stained chert

Likely quartz-rich sandstone (SiO₂) or microcrystalline quartz/chert with hematite

Red jasper (likely iron-rich chert)

Microcrystalline quartz, SiO₂, colored mainly by hematite/goethite

Limonite/Goethite Concretion

Goethite (FeO(OH))

Quartz (Raw Chunk)

Silicon Dioxide (SiO2)

Green Calcite

Calcium Carbonate (CaCO3)

Quartz

Silicon Dioxide (SiO2)

Pyrite

Iron Sulfide (FeS2)

Quartz

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz (Milky / Massive Quartz)

Silicon Dioxide (SiO2)

Pyrite

Iron Sulfide (FeS2)

Ferruginous Quartz on Ironstone

Silicon Dioxide (SiO2) with Hematite (Fe2O3)

Quartz Druzy / Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Calcite

Calcium Carbonate (CaCO3)