Organic (Geological Interest)

Chert (Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Hypersthene (or Enstatite/Ferrosilite)

Orthopyroxene series (Mg,Fe)SiO3 - specifically, historically hypersthene (intermediate member) now referred to as Enstatite (Mg-rich) or Ferrosilite (Fe-rich)

Cockle Shell (Fossil or Recent)

Class Bivalvia, Family Cardiidae (e.g., Cerastoderma edule for common cockle)

Chert (Limestone-based)

Silicon dioxide (SiO2)

Chert (variant Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2)

Chrysanthemum Stone

Celestine (SrSO4) or Calcite (CaCO3) in Limestone/Porphyry matrix

Chert (Jasper variety)

Cryptocrystalline Quartz (SiO2)

Chert / Jasper

Microcrystalline Quartz (SiO2)

Chert (with Limestone matrix)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Greenschist

Greenschist facies rock

Chert (Jasper)

Microcrystalline Quartz (SiO2) with Iron Oxide inclusions

Pyrite

Iron Sulfide (FeS2)

Fossiliferous Limestone (Coquina)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Chert (Jasper/Flint variant)

Microcrystalline Quartz (SiO2)

Chert (often called Flint in this variation)

Silicon dioxide (SiO2) - Microcrystalline quartz

Chert (variations include Flint or Jasper)

Silicon Dioxide (SiO2)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Pyrite in Shaly Matrix

Iron Sulfide (FeS2)

Chert (containing Flint and Calcareous inclusions)

Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3) impurities

Chert (Brown Variety)

Microcrystalline quartz (SiO2)

Agatized Fossil (Druzy Agate)

Silicon Dioxide (SiO2) replacing organic matter

Pyrite

Iron Sulfide (FeS2)

Chert / Flint

Silicon Dioxide (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert (Jasper/Chalcedony variety)

Microcrystalline Quartz (SiO2)

Chert (White-Grey variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Yellow Jasper / Chert

Jasper (Silica/Quartz) - SiO2

Fossil Shell (Bivalve)

Phylum Mollusca, Class Bivalvia (typically composed of Calcium Carbonate / CaCO3)

Chert (White Chert/Flint)

Chert (SiO2)

Chert (specifically Flint or Common Chert)

Silicon Dioxide (SiO2)

Chert (variations include Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Fossil Coral (Rugosa or Solitary Coral)

Rugosa (Order), often referred to as 'Horn Coral' (Lithostrotionella or Grewingkia)

Petrified Wood

Silicified Wood (primarily SiO2)

Banded Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Moss Agate

Silicon Dioxide (SiO2) with Manganese or Iron Oxide inclusions

Chert (Jasper/Flint variant)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Fossilized Coral

Cnidaria (Anthozoa), often replaced by Calcium Carbonate (CaCO3) or Silica (SiO2)

Jasper (specifically a banded or dark variety)

Silicon Dioxide (SiO2) with impurities