Sedimentary (Biogenic Sediment Or Biological Remain)

Kidney Stone (Urolith)

Calculus renalis (Biogenic mineral aggregate)

Fossiliferous Sedimentary Rock

Sedimentary Rock with Invertebrate Fossil Imprint

Stromatolite

Biogenic Sedimentary Rock (Precambrian Stromatolite fossil)

Banded Chert

Microcrystalline Quartz (SiO2)

Sea Shell (Fighting Conch Fragment)

Calcium Carbonate (CaCO3) - Strombus alatus fragment

Fossiliferous Limestone (containing Brachiopods)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Jasper containing fossilized inclusions

Silicon Dioxide (SiO2) with trace impurities and biogenic inclusions

Hag Stone (Holey Rock / Fossiliferous Limestone)

Limestone (CaCO3) with natural erosion / fossil cavities

Fossiliferous Limestone (Shell Fragment)

Biogenic Limestone (Calcium Carbonate / CaCO3)

Limitation Concretion

Ironstone Concretion (Goethite/Limonite)

Fossil shell fragment

Indeterminate molluscan bioclast, likely aragonite or calcite

Oyster Shell (Aragonite/Calcite)

Calcium Carbonate (CaCO3)

Bivalve Fossil (Clam)

Class Bivalvia, likely Mercenaria or similar genus

Hag Stone (Banded Chert or Limestone with Borehole)

Microcrystalline Quartz (Chert) or Calciferous Siltstone (CaCO3/SiO2)

Fossiliferous Rock (Invertebrate Fossil in Matrix)

Fossiliferous limestone or shaly matrix containing skeletal fossil remains

Fossil Shark Tooth

Chondrichthyes dentition (Fossilized Tooth)

Fossilized Shark Tooth

Chondrichthyes (Class)

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with Bioclasts

Fossil bivalve shell

Likely an internal mold or mineralized shell of a brachiopod or small bivalve; exact taxonomy requires locality and diagnostic details

Banded Chert Pebble

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Fossil Shell in Sedimentary Matrix

Bivalvia (fossil) in Calcium Carbonate Matrix

Sandstone concretion

Arenite sedimentary rock (concretion/nodule)

Tumbled dark stone, possibly chert or basalt

Indeterminate; likely fine-grained basalt (plagioclase–pyroxene) or microcrystalline chert (quartz, SiO₂)

Rounded brown pebble, likely chert or iron-stained quartzite

Chert (microcrystalline quartz, SiO₂) or quartzite (recrystallized quartz, SiO₂)

Fossil Bivalve Shell

Class Bivalvia (e.g., Veneriidae family)

Devil's Toenail

Gryphaea (extinct genus of foam oysters, typically composed of Calcite CaCO3)

Kidney Stone (Calcium Oxalate / Uric Acid)

Calcium Oxalate Monohydrate (Whewellite) / Calcium Oxalate Dihydrate (Weddellite)

Fossilized Shark Tooth (Partial) or Coprolite

Elasmobranchii (fossil) or Coprolite (trace fossil)

Flint (chert), likely brown flint

Microcrystalline quartz/chalcedony (SiO₂)

Seashell Fossil

Mollusca (Bivalvia)

Conglomerate

Conglomerate (clastic sedimentary rock)

Polished brown flint/chert (likely)

Microcrystalline quartz, SiO₂ (chalcedonic flint/chert)

Petrified Wood (Agatized/Silicified Wood)

Silicified Wood / Chalcedony (SiO2)

Shell Cameo

Cypraecassis rufa (Bullmouth Queen Helmet Shell)

Polished septarian nodule

Calcite–aragonite–barite septarian concretion, commonly in a claystone or limestone matrix

Fossiliferous Limestone (Gritstone/Marl)

CaCO3 (Calcium Carbonate) with Fossil Inclusions

Petrified Wood with Lichen

Silicified Wood (SiO2) colonized by crustose lichens

Shark Tooth Fossil

Selachii fossil

Weathered flint or chert fragment

Microcrystalline quartz (SiO₂), likely chert/flint

Fossilized shell fragment

Indeterminate fossil mollusk; likely a silicified or mineral-replaced bivalve/gastropod fragment

Botryoidal calcite (likely calcite concretion)

Calcite, calcium carbonate (CaCO₃)