Organic (Sedimentary Context)

Coral Fossil (Petrified Coral)

Scleractinia (Order) - Calcified Fossil Skeleton (CaCO3)

Banded Chert (with Quartz Vein)

Microcrystalline Silica (SiO2)

Chert (Chert Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Massive Cryptocrystalline Quartz (Chert/Chalcedony Pebble)

Silicon Dioxide (SiO2)

Travertine (often colloquially called Tufa)

Chemical Sedimentary Calcium Carbonate (CaCO3)

Chert (specifically Iron-stained River Cobble)

Silicon Dioxide (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Green Banded Chert (Agate/Jasper)

Silicon Dioxide (SiO2) with trace impurities of Chlorite or Glauconite

Coquina

Biogenic Limestone (Calcium Carbonate, CaCO3)

Glauconitic Sandstone

Glauconitic Quartz-Wacke / Sandstone (Fe(II),Fe(III),Al,Mg)2-3(Si,Al)4O10(OH)2

Amber

Succinite (fossilized resin)

Petrified Wood

Silicified Wood (SiO2)

Moss Agate

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

Chert (Brown variety / Common Jasper)

Microcrystalline Quartz (SiO2)

Chert (variously identified as Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

Septarian Nodule (Thunder Egg)

Septarian Concretion (CaCO3 + CaMg(CO3)2 + SiO2)

Petrified Wood

Silicified Wood (primarily SiO2)

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Ferruginous Sandstone (Ironstone)

Arenite with Iron-Oxide Cement (FeO(OH)·nH2O / Fe2O3)

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Limestone

Calcium Carbonate (CaCO3)

Moss Agate

Silicon Dioxide with inclusions (SiO2 + impurities)

Petrified Wood

Silicified Wood (primarily SiO₂ - Silicon Dioxide)

Graphite

Graphite (C)

Fossilized Wood (with Coal and Limonite)

Petrified Wood (Silicified or Carbonized Flora)

Petrified Wood

Silicified Wood (primarily SiO2)

Petrified Wood

Silicified Wood (SiO2)

Chert (with Quartz vein)

Chert (Silicon Dioxide, SiO2)

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood (Agatized/Silicified Wood)

Silicified Wood / Chalcedony (SiO2)

Chert (Flint)

Chert (Cryptocrystalline variety of Quartz, SiO2)

Fossiliferous Brachiopod in Shale

Brachiopoda (Phylum) preserved in Carbonaceous Shale

Petrified Wood

Silicified Wood (primarily SiO₂ / Silicon Dioxide)

Chert (variant Flint/Jasper)

Microcrystalline Opaline Silica (SiO2)

Coquina

Biogenic Limestone (Calcium Carbonate - CaCO3)

Fossil Shell (Bivalve)

Class Bivalvia (Likely a member of the Ostreidae or Gryphaeidae family), CaCO3

Amber / Copal

Fossilized Tree Resin (Succinate)

Pickled Dragon Eggs (Fictional Interpretation: Purple Agate or Amethyst Geodes)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Septarian Nodule or Mud Crack Fossil

Septarian Nodule (Concretion)

Chert (variations include Flint or Jasper)

Silicon Dioxide (SiO2)