Sedimentary (Biogenic)

Sandstone Moqui Marble (Concretion)

Iron oxide concretion (Hematite/Goethite and Quartz)

Chert (often called Flint or River Stone)

Chert (Microcrystalline Silicon Dioxide, SiO2)

Petrified Wood

Silicified wood (Quartz/Chalcedony/Opal replacing organic matter)

Chert (and/or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Ironstone (Limonitic Sandstone)

Ferruginous Sandstone (rich in Limonite: FeO(OH)·nH2O)

Chert (Jasper/Flint variety)

Microcrystalline quartz (SiO2)

Anthracite

Anthracite Coal

Fossilized Coral (Honeycomb Coral)

Favosites (extinct genus of tabulate corals), CaCO3 (Calcium Carbonate)

Chert (Jasper variety)

Silicon Dioxide (SiO2) with iron oxide impurities

Chert (specifically Flint or Jasper variant)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone Concretion

Septarian or Carbonate-cemented Sandstone Concretion

Chert (Flint)

Silicon Dioxide (SiO2)

Fossil Coral (Petoskey Stone / Rugose Coral)

Hexagonaria percarinata (Order: Rugosa, Fossilized Calcium Carbonate CaCO3)

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Stromatolite

Cyanobacteria fossilized formation (CaCO3)

Chert (specifically Red Chert / Jasper)

Silicon Dioxide (SiO2)

Bauxite

Bauxite (Al(OH)3, AlO(OH))

Crinoid Stem Columns (Fossil)

Crinoidea (Class); often composed of the mineral Calcite (CaCO3)

Petrified Wood

Silicified Wood (SiO2)

Yellow Jasper (Iron-stained Quartz)

Jasper (Silicon Dioxide, SiO2 plus iron oxide impurities)

Chert (Yellow or Tan Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Ferruginous Chert (Jasper)

Silicon Dioxide (SiO2) with iron oxide inclusions

African Turquoise

Teal Jasper (Macro-crystalline Quartz/Sio2 + Inclusions of Copper, Iron, and Manganese)

Chert (Yellow Jasper)

Microcrystalline Quartz (SiO2)

Fossiliferous Chert (Chert with Crinoid Stem Impression)

Chert (SiO2) with fossil Anthozoan or Crinoid columnals

Chert (often called Flint)

Chert (Microcrystalline Silicon Dioxide, SiO2)

Yellow Jasper

Jasper (SiO2) with iron hydroxide inclusions

Chert (specifically Flint or Gray Chert)

Silicon Dioxide (Microcrystalline Quartz), SiO2

Chert (variations include Flint or Jasper)

Silicon Dioxide (SiO2)

Flower Jasper

Agatized Fossil Coral / Chalcedony (SiO2)

Jasper

Silicon Dioxide (SiO2)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Jasper

Silicon dioxide (SiO2) with impurities

Ironstone Concretion

Limonitic/Hematitic Concretion

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Red Sandstone

Arenite (primarily Quartz SiO2 with Hematite Fe2O3 cement)

Red Sandstone

Arenite (ferruginous sandstone)

Petrified Wood

Silicified Wood (SiO2)

Jasper with Quartz Druzy

Silicon Dioxide (SiO2)

Sandstone (Quartzose Sandstone)

Arenite (composed primarily of SiO2)

Red Jasper

Microcrystalline quartz (SiO2) with Hematite (Fe2O3) impurities