Organic Specimen (Fossil)

Sedimentary Strata of the Badlands (Mudstone, Siltstone, and Sandstone)

White River Group (Brule and Chadron Formations)

Fossilized Brachiopod Shell

Phylum Brachiopoda (likely Order Spiriferida or Strophomenida)

Amber

Succinite (approximate formula C10H16O)

Sandstone Clast

Arenite (primarily SiO2)

Sandstone (Quartz-rich)

Arenite

Slate

Slate (foliated metamorphic rock rich in quartz, sericite, and chlorite)

Sandstone

Arenite (primarily SiO2 with various cementing agents)

Sandstone

Arenite (Sedimentary rock comprising sand-sized grains)

Sandstone

Arenite (primarily Quartz, SiO2)

Sandstone

Arenite (primarily SiO2)

Limestone

Calcium Carbonate (CaCO3)

Orthoceras fossil in limestone

Orthoceras (extinct genus of cephalopod)

Weathered sandstone pebble

Quartz-rich sandstone, likely ferruginous sandstone

Milky Quartz

Silicon Dioxide (SiO2)

Crinoid Stem Fossil (in Chert or Limestone Matrix)

Crinoidea (Class) - Calcium Carbonate (CaCO3)

Limestone

Sedimentary Rock (Primarily Calcium Carbonate, CaCO3)

Shale

Argillite / Shaly Mudstone

Ferruginous Sandstone (Gozzanous)

SiO2 (Quartz) with FeO(OH) (Goethite) or Fe2O3 (Hematite) coating

Chert (Green Jasper)

Microcrystalline Quartz (SiO2) with iron silicate inclusions

Banded Chert

Silicon dioxide (SiO2) - Microcrystalline Quartz

Petoskey Stone

Hexagonaria percarinata

Fossilized Coral (Petoskey Stone / Favosites)

Hexagonaria percarinata / Favosites sp.

Shale with Iron Oxide Staining

Fissile Mudstone (primarily clay minerals and quartz)

Hag Stone

Perforated Quartz / Sedimentary Rock

Sandstone (Quartzite-leaning)

Arenite (primarily SiO2)

Sandstone

Arenite (SiO2 principal)

Sandstone

Arenite (primarily SiO2)

Orbicular granite (likely larvikite/rapakivi-type granite)

Granite; chiefly quartz, alkali feldspar, plagioclase, with dark biotite/amphibole and iron-oxide veining

Limestone

Calcium Carbonate (CaCO3)

Sandstone

Arenite (SiO2 based typically)

Quartzite River Rock with Dendrites

Metamorphosed Quartz-rich Sandstone with Manganese Oxide (MnO2) inclusions

Concretion

Septarian Concretion (Clay-Ironstone Nodules)

Yellow Chert (Yellow Jasper)

Silicon Dioxide (SiO2)

Sandstone

Arenite (SiO2 primarily)

Chert

Chert (Microcrystalline Quartz, SiO2)

Amber

Succinite

Red Sandstone

Arenite (Ferruginous Sandstone)

Sandstone (River Pebble)

Arenite (primarily SiO2)

Blue Apatite

Apatite - Ca5(PO4)3(F,Cl,OH)

Chert (often called Flint)

Chert (Cryptocrystalline Silica, SiO2)

Limestone (Buff/Tan)

Calcium Carbonate (CaCO3)

Weathered vuggy quartz-rich rock (probable silicified limestone or quartz breccia)

Microcrystalline quartz (SiO₂) with calcite (CaCO₃), iron oxides, and minor clay minerals