Organic Specimen (Fossil)

Sandstone (lithic wake/graywacke variety)

Arenite/Greywacke (SiO2 with lithic fragments)

Amber

Succinite (C10H16O)

Tumbled amber

Fossilized tree resin; commonly succinite (organic resin, not a mineral)

Iron-stained limestone or coral fragment

Calcite-rich carbonate rock; chiefly CaCO₃ (exact identification is uncertain from the image)

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with Bioclastic Inclusions

Limestone

Calcium Carbonate (CaCO3)

Petrified Wood

Silicified Wood (primarily SiO2)

Fossiliferous Limestone (Coquina-like)

Biogenic Limestone

Fossilized Coral

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

Petrified Wood

Silicified Wood (primarily SiO2)

Sandstone (with Chert/Quartzite nodules)

Clastic sedimentary rock (primarily SiO2)

Fossil coral (likely solitary rugose coral)

Rugosa; possibly genus Heliophyllum or similar

Chert (and Jasper)

Microcrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (primarily SiO2)

Chert (Jasper/Flint variety)

Microcrystalline quartz (SiO2)

Limestone

Calcium Carbonate (CaCO3)

Chert Pebble

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (primarily SiO2)

Bituminous Coal

Bituminous coal (Organic Sedimentary Rock)

Fossiliferous Limestone (with Rugose Coral)

Limestone with Tetracoralla (Rugosa) fossil

Stromatolite

Biogenic Sedimentary Rock (composed predominantly of CaCO3)

Gastropod Fossil (Snail)

Gastropoda (Internal mold/Steinkern)

Sandstone (Quartz-rich)

Arenite (composed primarily of SiO2)

Amber

Succinite (Fossilized Tree Resin)

Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Paper (Cellulose)

Cellulose (C6H10O5)n

Glauconitic Sandstone (Greensand)

Glauconitic quartz wacke or arenite

Petoskey Stone

Hexagonaria percarinata (Fossilized rugose coral)

Brachiopod or Bivalve Fossil in Limestone

Phylum Brachiopoda or Bivalvia (embedded in Calcium Carbonate matrix)

Amber

Succinite (Fossilized Resin C10H16O)

Sandstone (likely Graywacke or Arkose variant)

Clastic Sedimentary Rock (SiO2 with assorted lithic fragments)

Chert (Banded)

Silicon Dioxide (SiO2)

Fossilized ammonite (likely weathered ammonite cross-section)

Ammonoidea; commonly Jurassic–Cretaceous ammonite fossils replaced by calcite or aragonite

Polished ammonite fossil

Ammonoidea (likely a Jurassic or Cretaceous ammonite), preserved in limestone/mudstone

Fossiliferous Chert (Gryphaea Fossil)

Silicon Dioxide (SiO2) with Calcitic Mollusk Remnants

Glauconitic Sandstone

Glauconitic Sandstane (containing K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2)

Banded Agate / Shell Fossil Fragment

Silicon Dioxide (SiO2) / Calcium Carbonate (CaCO3)

Petrified Wood

Silicified Wood (primarily quartz/chalcedony replacing organic wood structure, SiO2)

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified wood (primarily quartz, SiO2)

Red Sandstone

Arenite (Ferruginous Sandstone)

Fossilized Oyster (Devil's Toenail)

Gryphaea (extinct genus of bivalve mollusks)