Marble

Serpentine

Antigorite, Lizardite, or Chrysotile (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4

Chert (with Quartz vein/coating)

Microcrystalline Quartz (SiO2)

Glauconitic Sandstone (Greensand)

Glauconitic Quartz Arenite (Formula: (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)

Fossil Coral (Rugose Coral)

Rugosa (extinct order); typically composed of Calcite (CaCO3) or replaced by Quartz (SiO2)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Sandstone (likely Greywacke or Siltstone variety)

Arenite / Siltstone (primarily SiO2)

Amber

Succinite (Resin C10H16O)

Sandstone (with Feldspathic/Arkose qualities)

Arenite (primarily SiO2 with KAlSi3O8 components)

Fossilized Horn Coral

Order Rugosa (Rugose Coral)

Greywacke with Quartz Vein

Matrix: Impure Sandstone (SiO2 + varied clasts), Veins: Quartz (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Limestone

Calcium Carbonate (CaCO3)

Ammonite Fossil

Ammonoidea (typically preserved as Calcite CaCO3 or Pyrite FeS2)

Orange Calcite

Calcium Carbonate (CaCO3)

Fossiliferous Limestone with Crinoid stems

Calcite-rich Biogenic Sedimentary Rock (CaCO3)

Oolitic Ironstone

Sedimentary Ooidal Ironstone (Limonite/Hematite mixture)

Chert (Quartz Variety)

Chert (Silicon Dioxide, SiO2)

Fossilized Coral

Scleractinia (fossil order), primarily Calcium Carbonate (CaCO3)

Chert (Nodule)

Silicon Dioxide (SiO2)

Chert (or Flint)

Chert (Sedimentary Cryptocrystalline Sio2)

Yellow Calcite

Calcium Carbonate (CaCO3)

Hag Stone

Siltstone or Fine-grained Sandstone with boring (e.g., Lithophaga impact)

Sandstone (Calcareous or Ferruginous)

Clastic sedimentary rock (SiO2 with CaCO3 or Fe2O3 cement)

Chert (Jasper/Flint variant)

Silicon Dioxide (SiO2)

Chert (and Flint)

Microcrystalline Silica (SiO2)

Chert (Cherty Limestone / Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Rough Diamond

Native Carbon (C)

Chert (Yellow Jasper/Quartzite Pebble)

Microcrystalline Silicon Dioxide (SiO2)

Fossil Sand Dollar (Echinoidea)

Phylum Echinodermata, Class Echinoidea (likely Dendraster or Scutella)

Chert (specifically Flint or Jasper variant)

Microcrystalline quartz (SiO2)

Asphalt (Bituminous Slate/Sandstone)

Asphaltum / Bituminous Rock

Chert (Jasper/Agate variety)

Microcrystalline Quartz (SiO2)

Chert

Chert (Microcrystalline Quartz, SiO2)

Serpentinite (River Pebble)

Serpentinite (complex of Antigorite, Lizardite, and Chrysotile: Mg3Si2O5(OH)4)

Limestone

Calcium Carbonate (CaCO3)

Basalt (Polished pebble)

Basalt (Aphanitic mafic volcanic rock)

Fossilized Shark Tooth

Fossil Chondrichthyes (various genera such as Carcharias or Odontaspis)

Chert (Yellow/Tan variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (and/or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Industrial Diamond (Bort or Boart)

Diamond (pure Carbon, C)

Chert (specifically a Chert Nodule or Flint)

Cryptocrystalline Quartz (SiO2)

Quartz (Water-worn Pebble)

Silicon Dioxide (SiO2)