Organic Mineraloid

Chert (and Flint)

Silicon Dioxide (SiO2)

Fossil Coral (Rugosa or Solitary Coral)

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

Chert (Holey Stone)

Microcrystalline Quartz (SiO2)

Ironstone Concretion (Ironstone Gourd)

Limonite/Goethite Concretion (FeOO(H))

Pink Opal

Hydrated silicon dioxide (SiO2·nH2O) with inclusions

Chert (Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Limestone

Calcium Carbonate (CaCO3)

Moss Agate

Silicon Dioxide with inclusions (SiO2 + impurities)

Shale or Siltstone

Sedimentary Clastic Rock (Variable mineral composition including quartz and clay minerals)

Moss Agate

Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxide

Chert (Brecciated Chert)

Silicon Dioxide (SiO2)

Fossilized Sand Tiger Shark Tooth

Carcharias taurus / Striatolamia macrota (mineralized as Hydroxylapatite/Francolite)

Dendritic Agate / Moss Agate

Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions

Green Moss Agate

Silicon Dioxide (SiO2) with inclusions of hornblende or chlorite

Moss Agate

Silicon Dioxide (SiO2) with inclusions of hornblende or chlorite

Moss Agate

Chalcedony (Silicon Dioxide, SiO2) with dendritic inclusions

Shale

Clastic sedimentary rock (primarily clay and silt minerals)

Pearl

Pearl (Calcium Carbonate with organic conchiolin, CaCO3)

Amber (Cherry or Red variety)

Succinite (with various trace amounts of organic compounds)

Bituminous Coal

Organic-rich sedimentary rock (Complex hydrocarbons)

Blue Agate (Tumbled and Dyed)

Silicon Dioxide (SiO2) with likely organic dyes

Fossiliferous Limestone (Crinoidal)

Calcite-bearing bioclastic packstone (CaCO3)

Chert (Jasper-like Silicate)

Microcrystalline quartz (SiO2)

Petrified Wood

Silicified wood (Quartz/Chalcedony - SiO2)

Chert (specifically Flint or Gray Chert)

Silicon Dioxide (SiO2)

Chert (Yellow Chert/Flint)

Silicon Dioxide (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Chert (and/or Chalcedony)

Microcrystalline Silica (SiO2)

Chert (and Quartz Gravel)

Chert (Cryptocrystalline Quartz, SiO2)

Chert (Yellow/Tan Variety)

Chert (SiO2)

Chert (specifically Tan/Yellow Chert)

Silicon Dioxide (SiO2)

Fossiliferous Limestone

Calcite-rich Sedimentary Rock (CaCO3)

Chert (within Asphalt)

Chert (SiO2)

Jasper (specifically a banded or dark variety)

Silicon Dioxide (SiO2) with impurities

Chert (Jasper focus)

Silicon dioxide (SiO2) - Microcrystalline Quartz

Chert (with Quartz veins)

Microcrystalline quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline quartz (SiO2)

Chert (often called Flint or Jasper)

Silicon Dioxide (SiO2)

Fossiliferous Limestone (Gritstone/Marl)

CaCO3 (Calcium Carbonate) with Fossil Inclusions

Chert (varietal: Jasper or Ironstone nodule)

Microcrystalline Quartz (SiO2) with iron oxides