Marble

Ironstone Pebble

Ferruginous sedimentary rock (Fe2O3 / FeO(OH) mixed with SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Chert / Jasper

Sedimentary Cryptocrystalline Quartz (SiO2)

Chert (Flint/Jasper variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Diamond (as set in a gold ring)

Carbon (C)

Turquoise and Red Coral

Turquoise: CuAl6(PO4)4(OH)8·4H2O; Red Coral: Corallium rubrum (organic gemstone)

Ammonite Fossil

Ammonoidea (subclass)

Serpentinite

Serpentinite (composed primarily of mineral group (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4)

Diamond

Native Carbon (C)

Ironstone Concretion (Pot Stone)

Siderite or Limonite Concretion (FeCO3 or FeO(OH)·nH2O)

Banded Chert

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Jasper

Silicon dioxide (SiO2)

Yellow Jasper / Chert

Silicon Dioxide (SiO2) with Goethite or Limonite inclusions

Limestone with Quartz or Calcite Veining

Calcium Carbonate (CaCO3) matrix with SiO2 or CaCO3 inclusions

Fossilized Coral (Petoskey-like or Favosites)

Anthozoa (Fossilized Coral)

Orthoceratid Fossil in Limestone

Orthoceras (extinct genus of Nautiloid Cephalopod)

Diamond

Carbon (C)

Fossil Coral (Rugose Coral Fragment)

Rugosa (extinct order of solitary and colonial corals)

Favosites (Honeycomb Coral Fossil)

Favosites (Genus of extinct tabulate coral)

Megalodon Shark Tooth Fossil

Otodus megalodon

Coquina / Shelly Limestone

Bioclastic Limestone (composed of CaCO3)

Banded Chert

Silicon Dioxide (SiO2)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper/Flint Pebble)

Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)

Fossil Shark Tooth (Otodus obliquus)

Otodus obliquus; hydroxyapatite (mineralized form Ca5(PO4)3(OH))

Red Chert (Jasper)

Chert / Microcrystalline Quartz (SiO2)

Coquina

Coquina (Bioclastic Calcarenite)

Chert (Tan/Brown variety)

Chert (Silicon Dioxide, SiO2)

Chert (often called Flint in this context)

Silicon Dioxide (SiO2)

Coquina / Fossiliferous Limestone

Fossiliferous Calcarenite (Calcium carbonate, CaCO3)

Fossil Coral

Scleractinia (Anthos), primarily Calcium Carbonate (CaCO3)

Chert (Tan/Yellow variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Diamond (Faceted)

Carbon (C) - Diamond

Jasper and Chert Conglomerate

Ferruginous Microcrystalline Quartz (SiO2)

Sandstone (Ferruginous)

Arenite (Fe-oxide cemented)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Commonly known as Flint or Jasper when pigmented)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Oolitic Limestone

Oolitic Limestone (CaCO3)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Fossiliferous Limestone

Limestone with fossil inclusions (CaCO3)

Chert / Flint Nodules in Sandstone

Microcrystalline Quartz (SiO2) within Clastic Sedimentary Rock

Chert (Cherty Limestone or Flint)

Microcrystalline Silica (SiO2)