Fossil Coral (Petoskey Stone / Rugose Coral)
Hexagonaria percarinata (Order: Rugosa, Fossilized Calcium Carbonate CaCO3)
sedimentary
Category
Sedimentary (Fossil)
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Honeycomb Coral Fossil (Petoskey-type Coral)
Favosites (Extinct Colonial Tabulate Coral), CaCO3
sedimentary
Sandstone (lithic wacke/arenite)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Chert (Smooth River Pebble)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Weathered limestone or calcitic cave deposit
Calcite (CaCO₃), likely porous limestone/travertine
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Vesicular volcanic rock, likely pumice or scoriaceous rhyolite
Vesicular rhyolite/dacite; predominantly silica-rich volcanic glass with feldspar and quartz
igneous
Petrified Wood
Silicified Wood (SiO2)
mineral
Petrified Wood
Silicified Wood (SiO2 - Silicon Dioxide)
metamorphic
Sandstone
Arenite (primarily Quartz, SiO2)
sedimentary
Sandstone Concretion
Clastic Sedimentary Rock - Quartz Arenite / Sandstone
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Amber
Succinite (C10H16O)
mineral
Sandstone (likely a river or beach pebble)
Sandstone (a clastic sedimentary rock)
Sedimentary Rock
Sandstone
Sandstone (lithified quartz arenite, arkose, graywacke, etc. depending on composition)
Sedimentary Rock
Likely weathered chert or flint
Microcrystalline quartz (SiO₂), probably chalcedony/chert
sedimentary
Likely weathered limestone or calcite-rich stone
Limestone, primarily calcium carbonate (CaCO₃), possibly calcite
sedimentary
Chert (Chert Nodule)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Sandstone (Quartzose)
Arenite (predominantly SiO2)
sedimentary
Chert (Green variety)
Chert (Silicon Dioxide, SiO2)
sedimentary
Sandstone
Arenite
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Limestone (specifically Dolomitic/Crystalline Limestone)
Sedimentary Carbonate Rock (CaCO3 / CaMg(CO3)2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO₂)
sedimentary
Fossilized Sea Urchin Spines
Echinoidea (Cidaroid spines)
sedimentary
Slate
Foliated Metamorphic Rock (primarily composed of Muscovite, Chlorite, and Quartz)
metamorphic
Megalodon Shark Tooth (Partial Fossil)
Otodus megalodon (fossilized in Calcium Phosphate/Apatite)
Mineral/Fossil
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Porous Quartzite
Metamorphosed Quartz-rich Sandstone (SiO2)
metamorphic
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 cement)
sedimentary
Amber
Succinite (Fossilized Resin)
gemstone
Amber
Succinite (Fossilized Resin)
mineral
Tumbled black-and-white stone, likely dalmatian jasper
Quartz-rich porphyritic rhyolite (commercially called dalmatian jasper), with black aegirine/arfvedsonite-like inclusions
igneous
Unidentified River Rock or Mudstone
N/A (Generic rock fragment)
Sedimentary or Metamorphic
Petrified Wood
Silicified Wood (SiO2 - Silicon Dioxide)
mineral
Tumbled tree agate (dendritic agate)
Cryptocrystalline quartz, SiO₂, with manganese/iron-oxide dendrites
mineral
Beach Pebble (Basalt / Greywacke Gravel)
Mafic Volcanic Rock (Basalt)
igneous
Petrified Wood
Silicified Wood / Chalcedony (SiO2)
mineral
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Chert (Flint)
Chert (microcrystalline quartz)
sedimentary