Sedimentary (Fossil)

Slate

Foliated Metamorphic Rock (Mainly composed of Quartz, Illite, Chlorite)

Limestone

Calcium Carbonate (CaCO3)

Limestone

Calcium Carbonate (CaCO3)

Chert (Nodular Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Fossilized shell or brachiopod

Likely a calcareous brachiopod or bivalve fossil; exact identification requires clearer detail and scale

Fossilized turtle shell fragment

Testudines indeterminate; shell bone permineralized with silica/carbonate minerals

Fossil Coral (Petoskey Stone or Chain Coral Pebble)

Hexagonaria percarinata / Rugosa coral (CaCO3)

Quartz Geode

Silicon Dioxide (SiO2)

Fossilized coral (likely honeycomb or branching coral)

Fossil coral; probable Scleractinia or Tabulata, composition mainly microcrystalline CaCO₃

Limestone

Sedimentary Calcium Carbonate (CaCO3)

Shark Tooth Fossil

Lamniformes (Shark tooth fossil composed of Fluorapatite)

Orthoceras fossil in limestone

Orthoceras regulare (extinct nautiloid cephalopod)

Fossil Shark Tooth

Carcharhiniformes fossil (likely Carcharhinidae family)

Granite boulder

Granite, composed mainly of quartz, alkali feldspar, plagioclase, and minor mica/amphibole

Fossil coral fragment (probable)

Recrystallized fossil coral, commonly scleractinian or tabulate coral; exact identification requires magnification and locality

Petoskey Stone

Hexagonaria percarinata (Fossilized colonial rugose coral)

Siltstone

Siltstone (primarily SiO2 with clay minerals)

Fossilized Solitary Rugose Coral (Horn Coral)

Order: Rugosa (e.g., Grewingkia or Heliophyllum); composed of Calcite (CaCO3) or Silica (SiO2)

Sandstone (Ferruginous)

Ferruginous Sandstone (SiO2 with Fe2O3)

Limestone (Micritic)

Sedimentary rock mainly composed of Calcium Carbonate (CaCO3)

Fossilized bivalve shell

Bivalvia (likely a venerid or similar clam); shell composed mainly of CaCO₃ as aragonite/calcite

Shiva Eye Shell Fossil (Operculum)

Turbo marmoratus (Operculum)

Petoskey Stone (Fossilized Rugose Coral)

Hexagonaria percarinata

Petrified Wood

Silicified Wood (SiO2)

Sandstone (likely Arkosic or Quartzose)

Sandstone (SiO2 with inclusions)

Coral Fossil (Favosites)

Favosites (order Tabulata)

Limestone

Calcium Carbonate (CaCO3)

Fossil Coral (Petoskey Stone / Favosites / Charlevoix Stone)

Hexagonaria percarinata / Favosites (Cnidaria)

Shale (or Mudstone)

Laminose Mudrock (composition: clay minerals, quartz, and mica flakes)

Limestone

Calcium Carbonate (CaCO3)

Crinoid Stem Fossil

Class Crinoidea (Echinodermata)

Quartz-rich sandstone or granitic fragment

Likely quartz–feldspar sandstone; exact identification is uncertain from the photograph

Polished fossilized ammonite or nautiloid shell

Ammonoidea or Nautiloidea; originally aragonitic shell, commonly replaced by calcite or chalcedony

Quartz Geode

Silicon Dioxide (SiO2)

Mixed collection of natural stones

Several unidentified lithologies, likely including basalt, granite, quartzite, sandstone, and weathered metamorphic rocks

Fossilized bivalve shell in limestone

Calcitic fossil shell; likely an oyster or other rudist/bivalve (Bivalvia), preserved in carbonate rock

Sandstone (likely Calcareous or Micaceous)

Clastic sedimentary rock (primarily Quartz with Cementing Agents)

Limestone

Sedimentary Rock (Primarily Calcium Carbonate, CaCO3)

Fossil Coral (Petoskey Stone or similar)

Hexagonaria percarinata (Fossilized Rugose Coral)

Chert (also known as Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Vesicular volcanic scoria (likely basaltic scoria)

Scoria; predominantly iron- and magnesium-rich silicate glass with plagioclase, pyroxene, and possible olivine

Limestone

Sedimentary Calcium Carbonate (CaCO3)